Denture causing pain

Hi, my patient needs a distal extension partial denture for the lower. He has his two premolars on the left and one premolar on the right. Lots of bone. All three rct. He has percussion sensitivity on all of them. I sent him to endo and they said it’s bc he is only biting on those three and his pdl is inflamed. Every time I take an impression it hurts him. And his previous denture doesnt fit anymore and was hurting him. I am worried my denture won’t relieve the pain bc he wont be able to put it on bc it hurts him. He also has dementia and it’s very hard to tell him that he needs to keep it on.

Any suggestions?