Will this fit a size 12 1/2 man?

I’m a size thirteen and I got them to fit me. I had to stretch them a bit, but when I got them on they fit great.

Are these socks going to shrink?

Ours held up great and have been dried many times thus far.

My grandson wears a size 7 shoewhat size socks do i order

I ordered these socks for my male friend as an Xmas gift. I believe there is only one size. He wears a men's size 10 ten shoe and the socks fit fine. The cotton does shrink so that would help if the socks appear too large for your grandson. In the pictures, the socks appear to climb higher up on the leg that they actually do - these socks are traditional crew -type socks which don't climb high on the leg, i.e., meaning, on a man they do not rise above the top of the calf muscle. The socks faded with each dry so now my friend air-drys them on an indoor cloths hanger. If I were in your socks (haha, pun intended!), I'd buy the fewest I could so you can see them yourself to determine if they'll fit your grandson. Hope this helps!

Would you say these socks are quite thin, medium thick or quite thick?

These socks are medium thick, that to keep your feet cushioned and comfy. It could be perfectly matched up with your sneakers and slippers during the summer.