Welcome to the forum! My husband has HepC/cirrhosis and also the good gene/bad gene for alpha 1 anti-trypson deficiency. I tell you this to let you know that we are going down that road. My husband is on the list, but I can tell you it's a rough road wading through all the medical, etc....
Here's what I can share with you. Most of the time, if you have health insurance, the transplant center will file with the insurance you currently have. The financial department at the transplant center can help you and will direct you with getting fund raisers set up, etc to help offset some of the medical bills themselves. With regard to the medications he will need after the transplant, there are patient assistance programs out there that will help you get the medications. These patient assistance programs are through the pharmaceutical companies themselves. Another thought, is if the transplant center gets him in some clinical trial medications (which are done for rejection meds), they can help you there, too.
With regard to social security....absolutely have him apply for SSD. He may get denied the first time (which is the typical thing they do), but appeal every time!! If you have a social worker at the hospital/ transplant center you are working with, they can actually help you get all of it filed and get through the red tape. Once he is approved for SSD, in some states it automatically will qualify him for Medicaid and in some cases medicare. What I am not sure of is if he already has health insurance, whetherr it will just offset, or what. But, if he is deemed disabled, he probably will not be able to work anyway, so he would qualify for full benefits.
We had a social worker get our filing done, and it really seemed to go so much smoother than when we applied the first time, and he got approved. Once wee got approved, wee did qualify for a VERY small amount of SSI due to the fact that my income was so low. His medicaid benefits pay 100% for everrything (which is a HUGE blessing).
Now, my brother in law also had a liver transplant 18 years ago (and still doing fantastic) and from what I understand, he had alot of fundraisers and had medicaid as well to offset costs.
I Hope I have not confused you any more, just wanted to give a little insight and hopefully some pointers. I would definitely speak with a social worker, because that will be your biggest ally through all this......
You hang in there!