First, I would say you don't need to be a total jerk or a-hole to him about the situation.
I would go visit him in Jail and put 20-30 bucks in his canteen as a good gesture. And then ask him where he wants his stuff... because he can't come back to Grand Ma's house... Be respectful and show some sympathy toward his situation and that you can be open to helping him with reasonable needs while he is locked up. But once he gets out. He is on his own, and you are not to be bothered after he gets out.
Even so, when he gets out.... he will be back for more freeloading. I would move my mail box to a po box for a while and change all the locks. All the window at ground level deck screwed shut and motion lights front and back. Get a dog, no better early warning device than a dog.
With that said, keep in mind.... that you always read in the paper, how, "the body was found in a shallow grave..." So, when you get home. find a nice spot in the back and dig a deep hole. You need at least 4 feet or more. Another helpful hint that has worked for me in the past, when you dig out the top soil, put it in a pile by it's self on a tarp next to the hole, then place the subsoil on a different tarp on the other side of the hole. That way the soil goes back in the order it came in and the grass and leaf debris are undisturbed... except where the digging was done. This makes it a lot easier to conceal the place of disposal.. Cover the hole with a piece of plywood until you need to fill the hole back in.
If the day comes, that you have to fill the hole back in.... never, never say a word about it. Never.
