I haven't dealt with a snake prolapsed rectum, but I have in mammals. The sugar thing does really work. Fill a small container with sugar. Dip the prolapsed hind end into the sugar. Wait a day or so and it will be gone. In the animals I have done, it was unnoticeable that the prolapse even happened.

I'm wondering if this home remedy is effective in reptiles as well as mammals?

Hope that little mojo gets better. Looks painful