I am currently without an M14 type rifle, but I used to have one.
I did just finish my first .308 AR build last summer, and De Selby is right, it's a better rifle in almost every measurable way, if one is looking to go DO stuff with it.
That said, an AR ain't an M1A and rifle purchases don't have to make sense. I'll own another M1A to round out my .308 Battle Rifle collection (after I build an FAL). They are a thing to themselves and they are a LOT like a classic muscle car. Not a great car by actual driving standards, but if ou want one, and that style, not easily substituted either.
If he wants a semi-auto .308 to go shoot, get an AR or FAL (Probably just stick with an AR for the optics solution). If he wants an M14, the Springfield M1A Loaded MA9222(walnut stock) or MA9229 (OD Stock) are pretty nice and about $1400-ish