Have they definitely done all that they can? Have they fitted an assist pump in the hope of finding a donor? or is there a reason he is unsuitable?
What a terrible situation to be in, I really feel for you and your family.
My Dad passed away from a combination of heart failure and cancer. Hospice managed the cancer pain with medications. The failing heart meant he slept a lot and wasn't very alert even when he was awake. The poor blood flow to the brain kept him a bit foggy. He was too weak to move around so my husband and I took care of him, spent time with him. That's what he wanted the most, just having us nearby to hold his hand and knowing he wasn't alone.