The single best piece of advice I can give you is to take him some place like Cabelas and have him shoot some to see what suits him the best. Thats what I did with my dad and has soon as he shot the Parker Terminator HP he knew that that was the one he wanted.

You can also try using the search feature here and you will find hours of reading. As long as you stick with a good name brand like Excaliber, Tenpoint, or Parker (listed in no particular order) you will have an excellent xbow that will last a lifetime if cared for.

My dad bought his Parker Terminator HP from Wyvern last year and he is a wealth of information and his customer service is top notch.

Here is his contact info:

Wyvern Creations, LLC
235 North River Road
Lee, NH 03824
603-659-0575
603-502-3404

Bob