Help for Austin

My 24 year old grandson Austin, contracted Crohn's disease 2 years ago. He's 6' 4" and weighed #240 when he was healthy. He now weighs #150.
His condition has deteriorated in the last year until he was admitted to the hospital just before Thanksgiving in 2017. Luckily he has health insurance for the hospital and is beginning to show signs of improvement.
Here's why I want to help him:

Crohn's disease robs your body of calcium and a major symptom is that the victim's teeth rot away. Imagine being 24 and every tooth in your mouth is black and rotted to a sharp point!
I want to help him get his teeth repaired/replaced. A dentist I trust says it will cost $18,000 to surgically remove his teeth and clean any bone rot in his upper and lower jaws and then, make dentures for Austin.
Our family cannot afford that much and Austin's insurance does not cover teeth. I have never asked for help before but I cannot imagine going through life at 24 years old with a mouth full of fangs.
Can you help us help Austin?

Thanks for anything you can contribute.