HNI Vistor. Please accept my condolences.

I would say the 308 would be a good gun for your grandson.Unfortunately the Ruger Mini' s aren' t the most accurate rifles. The 223 is to small for deer especially with a young shooter. I would check your states requirements for minimum legal calibers.I wouldn' t even consider a 9mm for deer rifle or handgun.The Garand is to much rifle for a young person in IMHO.Go with the 308.
Ruger Redhawk