He constantly complains about "stuff" that didn't make it in the move. Although he had time to sort through prior to the packing, he didn't make any attempts. He is 90 and complaining about model airplane plans that he's going to use someday, spices that were tossed, a wet suit from the 60's, etc.....
I discussed how this makes us feel when he complains, and asked what we an do about it now? He stopped for awhile, but is back on it again. How do I steer him toward gratitude for the help instead of constant criticism about the job that was done?
Going forward, try to include him in any decisions and get him involved in activities (a local senior center, Veterans Groups, etc.) This may divert his attention and get him to start doing things that he enjoys.
It's a big job to take on an elder, yes. But if he knows his things are being treated cavalierly, he may decline more quickly. Ask him to tell you the history of the wetsuit, the model plans, and find out what he would like to do with his time now. He needs to occupy his time in a way that makes him happy, and still feel useful.
Think how You would feel. Good luck:)