I suppose I can't speak for your family and friends... But mine would certainly still want me around. (And I would undoubtedly want them around, if a tragedy such as this would happen to them.)
I say the same thing that was said before, but once I find out I'm still alive, I imagine I might be stubborn as all hell, fighting to hold onto what part of life I can.
But the way I see it - I don't want to hang around if I'm no longer a functioning, productive member of society. I don't want to be a leech. Paralyzed is one thing, but I know for sure eventually I will making a living will that mandates any plugs get pulled if I am unresponsive for some fairly short period of time... give it a week or two maybe. I don't care about percentages or hopes, unless it was a planned coma (for surgery of some sort).
I feel life and resources are married together quite strongly, and I don't want to simply waste resources keeping my life, if I'm not doing my part for society. Others may feel differently, of course.
However, as for the OP's story:
Damn, that girl is awesome. I hope the fiance is just as awesome as she is, because she remains in good terms with the one that essentially put her in her current place.
We all know about those signs that say no rough-horsing around shallow water (which I swear the signs even say 9' is shallow and thus no diving). But yet most of us play rough around in-ground pools all the time, and I'm pretty sure I've been pushed into, and probably pushed someone, into water less than 4' deep. That kind of accident is entirely possible, but we never think about it until we see it happen.
If I ever caused that to someone, I certainly would devote plenty of time to assist with that individual - but I wouldn't expect forgiveness.