It is not rocket science to load for the M1 Garand. One only has to be aware that the slow burning powders are not suitable. 4895 is THE M1 powder as it was loaded by the bajillions of rounds with 150 gr bullets in M2 ammo and with 174 gr bullets in M1/M72 ammo. Actually the gas system is designed around the M1 ammo which was loaded with 4895. Depending on the flavor (there are several different makes and also milsurp still around) of 4895 the 49 gr load mentioned is probably about right with a 150 Nosler BT. However as with all rifles your friend should work up to find what his rifle likes best. I'd suggest starting at 46 gr and work up in 1/2 gr increments. I usually find best accuracy with M1s in the 2800 fps range with 150 gr bullets and 4895 (most any flavor). Another good bullet to use in the M1 for hunting that feeds weel is the 165 Remington CoreLok. I'd also suggest getting the RCBS X-die (a small base die is not necessary for the M1) as it will give much longer case life and you will not have to trim the cases.
Larry Gibson