perhaps a taser if he gets in your face again?
serously, he knows mama has been supporting him now for 8+ years, he thinks this will continue indefinitely and he will be "needed" later as you advance in age. Telling him the truth now will save him in the long run from making your senior years filled with crazy.
He needs to be as self sufficient as possible and having a padded nest to land in complete with central AC, sleeping privacy, a full fridge and internet/tv/radio/clean laundry/bathrooms doesn't encourage him to take care of himself.
hopefully getting somewhere in therapy will teach him something.