I'm not sure what the poly limits are. I think that's OK for the PC version. I think I read somewhere that models could be up to 65,000. (?)
Still, 6500 might be alot, would be better if he could make a low poly version. I'm sure it would be easy for him and probably useful too.
The tools HE need sto export from Max are here:
http://www.interlopers.net/index.php?page=tutorials&id=24082
He can watch this vid on model requirements
www.generalvivi.lawgiver.us/downloads/3dsmax_compiling.zip
basically the model (even static) needs a 2 bone structure. Bone01 needs to be attached via Biped to the model. Then the model needs collision boxes, very simple convex shapes to block out the collision of the car. Each collision shape needs a smoothing group applied, each one needs a unique smoothing group. So the block for body of the car would be smooth group 1, the block for a wheel would be smooth group 2...
The collision model needs exported seperate from the model itself. So 2 files. Another if you have anims.
He can export with the materials in any format. TGA is good.
He can export as an smd. Then you need to follow those tut guidleines on how to get the model converted from an smd to an mdl (with a qc file). You don't need 3ds Max for that, he might not want to bother with that stuff and if he doesn't have TF2 he won't have the folder paths...
The materials file is something you'll need to make, just like the QC file for converting the smd to mdl. But the material just describes where the tex is, how shiny it is, what it sounds like, etc... There is info on this stuff on the valve wiki also.