Thats not as bad a truck as some think for an LD2500. The trans is or should be a 4l80E, not the normal 4l60 put in 6 lug trucks. Rear is was supposed to be a full floater, do not remember if it is the typical 9.5" or a 10.5" rear. power wise, being a 6 lugger, it is short of the 8 luggers, at 175 vs 185. Torque is around 330-350 vs 385. Being a 95, it is the first year of the electronic injection pump.
If it has some overheating issues, put the post 97 fan, dual t-state setup and that helps tremendously this issue. Also remember to use a robert shaw or std GM t-stat, not a stant or equal. As those do not flow as much water, and will cause some overheating too! You can also put a later model turbo on it, ie bigger capacity, that also help cool it better. If you have access to being able to time the motor, try to get it to -1.94. That seems to be the best place for that motor. The manual NV4500 5 sp option kept the engine cooler, and had better performance than the auto version.
At one time, TheDieselpage.com had some of the best info for how to take care, use, tune better etc the 6.5 motor. Not sure if that info is still on the site, hopefully it is. It helped a lot to keep my 96 6.5 moving. It was not the worst engine I had, not the best either. It worked well for what it was. With 175 hp it will not be a barn burner of a motor, but it will get the job done.
Hopefully your friend enjoys the truck.
Marty