Hello, all. My Dad is about 2 weeks out from ending his chemo and radiation. He still has excessive mucous in his mouth that he is constantly hacking up and spitting out. How long will this last??

Also, he is getting really tired of his Boost and Ensure drinks. He does not have a PEG and never had one. Today, I made him a drink with my juicer (kale, celery, carrots, apples) just to get some nutrients in him. He drank it, but didn't like the taste. He still has to have foods that are super smooth. I cooked him a cheesy, soft scrambled egg and he said the texture was bad. He says food is still grainy and tastes like gravel in his mouth. I'm wondering when the heck that will improve??
I feel like what he can try is super limited. Must be super smooth. Can't handle anything too cold, so there goes ice cream. He said he didn't think he should have peanut butter because it would be too sticky in his throat.
I have seen the suggested foods list, but wondered if ya'll had any other ideas.
Also--he has these deep cracks in his tongue. I assume these will heal up.