I did a wool-blend quilt with a pieced wool-blend top, wool batting, and wool-blend backing. It's very warm! I also did a second, substituting flannel for the backing. Both were tied. The flannel one is not itchy--the other is a bit, but only on bare skin, not through clothing or sleepwear.
The wool-blend was on sale (3.00 per yard), which is why I went with it. I washed it twice before cutting in very hot water and dried it very hot to check if it would go all wonky, but it didn't. I think I'd do the same with thrifted wool blankets.
I think your flannel/wool idea is a good one. If he finds it itchy, he could always turn it over!
