Glad to have you Nancy! And here's a warm welcome from sunny Nevada!
I have a feeling that one of the reasons your grandson doesn't know what he wants is that he doesn't know what's available to him. A hand made quilt is an awesome thing, and I'm so glad to see at least some younger people getting into it. I asked my niece what kind of quilt she wanted, and she didn't know, so I took her to my quilting room and just started pulling out quilts for her. By the time she found exactly what she wanted, she was in tears. She'd never seen a hand made quilt before, and was genuinely surprised at how much nicer they are than those you can buy in a store. LOL! Being fairly young, I expected her to go toward a more modern quilt, but no, she chose the most traditional quilt in the bunch.
Can you try showing your grandson quilts made from kits in an on line store, like Keepsake Quilting? Even if you don't use the kit, it might help him to choose a particular type of pattern or color he likes. I've done that as well, and it usually helps a lot. IMHO.