The injured person need to urge AMA to get this resolved.
Or further get in contact with the actual insurance company (AMA is rather an insurance broker), they can not just delay the payments forever because their
client does not respond.
I'd give them a few weeks and then probably get a lawyer involved. Also have the club contact their member and remind him of the problems, I can not see a club letting this person continue to fly as long as this is not resolved.