Dads Medical Bills due to PTLD

As many of you know, my Dad (David Northcott) had a Heart Transplant in June of 2014. The first year went well with a steady improvement over the first 14 months. Then they changed an anti-rejection medication that his body didn’t tolerate well at all. They insisted that he needed this medication and would raise a lower the dose but the negative effects still existed. This went on for 8 solid months with Dad feeling up and down not really able to do a whole lot. We finally got him off that medication but he was still feeling poorly.
In July he went back to the hospital for a 2 year follow-up. Turns out he had a lot of swollen lymph nodes and was promptly put back into the hospital for a week while they figured out the problem. He was then diagnosed with PTLD (Post Transplant Lymphoproliferative Disease). It is a form of Lymphoma cancer that is brought on mainly by the severely compromised immune system due to the Anti-Rejection Medications. It’s a not terribly common problem that we were warned about prior to transplant but we had little choice.
The hospital stay and the cancer treatments bills have started rolling in and the figures are staggering. I’m getting married and we’re trying to keep my sister in college. With only my mom working and my dad collecting disability it barely covers the household bills.
Any assistance would be greatly appreciated.
Thank You so much!!