Yes, you need a new will now anyway, correct? Go ahead and get one done.
Also - check and see, if you're in the US, I'm not sure but there may be some way to flag their passports that you have to consent to them leaving the country.
Now this is probably all just control issues and dragging his feet but I also worry a teeny bit about someone so unbalanced and his interest in your will. So I would have a new one drawn up ASAP that specifically disinherits him and sets someone else as executor of your estate. Then you can inform him you have a new will and that way he has less incentive to do anything dastardly.
(Funny side story - when I divorced I was entitled to keep a life insurance policy on my ex- at my cost - to cover the alimony in case he died. We already had a life insurance policy on him for $500k but he insisted that I reduce it to $250k ( remember I was paying the premiums) so that I couldn't "profit" from his death! Since I never threatened him or even gave him a hard time during the divorce I thought this projection was a manifestation of his guilt - as in, if he had been in my shoes he might have wanted to take out a contract on someone who had treated him as poorly as he had treated me lol!)
