You could try asking the nursing staff at the hospital he is in now if they could put you in touch with their duty social worker. Hopefully they would be able to have a chat to your family and assess your needs and get the ball rolling for when he's discharged.
I have always made my wishes clear to my relatives in the past which organs i would like to donate without carrying a card. You have convinced me that signing up is the best thing to do, so i have, and so has my Husband.