Your friend has all that is needed to access files on a NT4 server. No need to buy DAVE, although it is a nice package and its way faster than Appletalk on NT4. (By comparison, the Appletalk over IP stack included in W2K is 4 time fasters than the native Appletalk stack included in NT4,IIRC)
On his NT4 server, he has to install Services for Macintosh (see to server doc on how to do it).
Next, head over to the the control panels and use the Windows For Workgroup-style File Manager to set up an Macintosh share. Depending on the number of files shared, it may take a while until the share appear on the network.
On his Mac, your friend has to bind AppleTalk to his Ethernet adapter and he should be able to see the the NT4 server in the Chooser.
One caveat: the partition to be shared has to NTFS (so that NT can saves the Mac resource fork in an NTFS stream).