First, it should have had an OBD2 code scanner hooked up to read any stored codes, and if none are present (or even if they are, if it isn't resolved this way) a code scanner capable of Ford specific codes (an OBD2-only scan tool won't grab these), and ideally depending on the situation, a scan tool capable of live data to look at it while running, or failing to start.
I can't tell you if your mechanic is honest or not. It is quite possible that he observed buildup that caused your throttle body to stick, but that definitely would have caused a related Ford specific trouble code since the accelerator pedal resistor reading would be different than that of the double resistor reading from the throttle body. I mean that there is no (mechanical, steel) cable, is drive by wire throttle, AFAIK, so no cable to clean, but if the throttle body needed cleaning, he may have cleaned it. Hopefully, he used something non-abrasive as Ford usually coats the throttle body and without that coating it will stick more/sooner next time. I wouldn't call removing the coating, ruining the throttle body but some would. It would still work fine if nothing (else) is damaged, till it gets too dirty again.
This should be reasonably easy to check, remove the intake snorkel and look for throttle body deposits. There should be practically none yet if it has been cleaned recently, or if he just got off the bulk crusty stuff, still pretty smooth even if there is a varnishy coating he left behind.
Fast forward to now. Airbag problem won't keep the vehicle from running fine. What is "no power" meaning? You kind of had to have power to see an air bag light? No engine power as-in idles but can't accelerate, or something else? If there is still a throttle body problem, there should be a code set again even if cleared previously. I am not sure if that code would clear itself once the problem is fixed (and if it does, could take some driving cycles, not clear the moment it was fixed), or needs cleared but either way, you had observed the check engine light had gone off when you received the vehicle back last time, correct? And then it's coming back on again so a code whether same or different, should be present now.
You really really need the codes to second guess the mechanic's in-person evaluation. He might mean well and did exactly what seemed right at the time, or be incompetent, or be deceitful. There's no way to tell from the info provided, except that if he didn't attempt to fix anything, just cleared a code, he'd have to be young and foolish (or on drugs) to think he wouldn't have a come-back when the problem happened again, so if he seems to be a competent mechanic otherwise, then I would think that whatever he did, at the time he thought that solved the problem. There's too many variables there to really be sure.
The key here is still diagnosis, what is going wrong and I'm not clear on the exact state of the vehicle when that thing goes wrong. I read that you were driving and it stalled. Okay that could be caused by a lot of things from severe engine misfires from an electrical and/or coil problem, to low fuel pressure or vac leaks, to a position sensor intermittent fault, and more. I don't know a lot of the particulars about whichever engine Ford put in those (and probably at least a couple choices?), maybe a 2.0L Ecoboost?
It is unlikely that your driving caused any, or further damage, unless it had severe misfires and was dumping unburnt fuel into the catalytic converters and burnt them up, but you would notice it running badly, with check engine light on, and have to keep driving to put that much fuel out the exhaust to cause damage in the short term.
I would ignore the air bag light for the time being. That could be related and resolves itself if the main problem with running is something as simple as a basic electrical problem such as corroded battery terminals or chassis ground, alternator intermittently failing so low system voltage, or rodents attacked the wiring or ... there's really no substitute for being there with hands on the vehicle to check things, given the info provided.
However since it still isn't fixed, I would wonder if it is a good idea to take it back to the same mechanic. I'd call and get his thoughts and if it seems like he has a clue what to do next, then see if you can apply some or all of the $145 charged so far, to future repair(s). It did seem to run right when you drove it away from his shop, right? If so, that was about all he could do at the time ("IF" all you had for codes was one for throttle body incorrect position, something like that) , except if he didn't road test it for long so he didn't see the problem resurface due to that.
Since he has recently fiddled with the throttle body, one thing I'd check is whether the connector(s) for it got put back on fully, snapped/latched into position, and whether working on it might have disturbed any other wires or vacuum lines.
That's about all I have. When it stalls is when you need a scan tool ready to get codes and realtime readings of what is going on. A great bang for the buck scan tool combo is an ELM327 based dongle used with Forscan app on a phone, the wifi version of the dongle is needed for Apple phones and will work on android or windows devices, or cheapest for android phones is the bluetooth versions. It need not be an expensive one at all, that vehicle uses canbus so just about any generic ELM327 (often called v2.1 or 2.5 but not always) should work. The free demo of Forscan will pull codes and look at one sensor/stat (aka PID) at a time which might be enough to find the fault(s), or the paid Forscan lite version of the app is more functional. If you do get a generic ELM327 dongle, do not install/use any of the junk (maybe even malware) that comes on an included CD. Forscan app is all that you need for that vehicle and use of a dongle, though the free demo version won't clear codes. The free version of Torque app will, but in the long term of owning a Ford vehicle, it is well worth buying the Forscan lite app, only about $6 or so IIRC.
If you had any plans to change any vehicle programming (which is NOT needed to just repair it), then instead of a bluetooth or wifi dongle connected to a phone, you'd be better off getting an ELM327 that has a USB connection to a windows laptop (assuming you have a windows laptop, or tablet, IDK anything about windows phones and apps). The windows version of Forscan is both free and more featured, though to do certain kinds of programming, will require that you request a free trial extended license from the developer. I probably shouldn't have even included this paragraph, since the dongles themselves are dirt cheap (often $12 or less for generic brands) so if you were to get the wifi or bluetooth version, it's not a big spend to get a USB version later.