K.G.
yes! my daughter...now 15....had her "blankie" until she was 10 or so. She used to keep it under her other blankets, right next to her skin where it was nice and cozy. Eventually she just outgrew it....seeing the other girls at sleepovers didn't have one was a big help. We tried to take the blankie away on several occasions and it was so traumatic. I don't see any harm in allowing a child to sleep with a comfort item. They grow up soon enough!!
It sounds like he has outgrown the finger sucking already. Maybe give him the blanket back and see what happens!