Being a friend, in my opinion, is no excuse for not taking care of a living thing. If you lose a friend over something like this, when they are the one clearly at fault, they're not a very good friend or person for letting an animal suffer.
I'd call animal control, and let whatever happens, happen. Anything would be better for that poor snake then to lay around and suffer if it isn't taken care of.
Personally, I have done it. I do what's best for the animals well being. If someone is cruel or neglectful of an animal that they took into their care, they deserve whatever happens to them. Friend or not.