The number of times this scenario gets played.....and every time it takes action from the poster here, to get their A out of their hair finally. In some cases the "coming to get my stuff" cr*p went on for months, which caused continued pain, and a few times the A used their keys to come and go, which was scary.
None of his mess is your problem, so let him sort it out for himself.
All you need see to, is to change locks.....like NOW. Even getting a key back does not mean he does not have a copy. Changed locks means he stays out of your home.
Either put his stuff where he can get it, and tell him that there is a collect deadline or it is dumped......or get a storage lock up, IN HIS NAME, pay the first month as a "bye bye" gift and give him the key.
You then get to take care of important issues, like yourself and your puppies.
God bless