If it comes to a critical point: wad some paper or something and put it in your tank's hide. Make sure you can only see a dark shadow. Now go buy a Tupperware container and set up his environment in that (with gauges and a heat source and all that).

But ideally you could have him stay with a friend.

But honestly, if your mother is so afraid of the snake that she'd kill him, I doubt she'd come near him to do so. Education can go a long way.