Baby Sitting A Berm

[Zoo Nanny]

That's a really nice thing for you to do. For your protection I would like to suggest a couple of things. I hope you don't mind or are offended by any of this.
First thing have him supply a health certificate from a vet stating that the snake is in good health prior to coming. Get as much information as you can in writing from the owner concerning the care and requirements needed for the snake. Also phone numbers for him and emergency numbers for contacts. Dates of stay are very important in the event of abandonment and also exact dietary requirements along with a signed agreement for payment of foods. Even though you know most of this information get it in writing from him. It will protect you in the event of misfortune.
Be sure to have him sign a waiver for emergency care with your vet. You could even have him visit your vet to sign a waiver there giving you authority to have the snake treated in the event of illness or emergency. Include on the waiver that he takes responsibility for payment. My vet and I have worked out a protocol of steps in the event of an emergency. I take the animal to her and from the office we call the owner with her on one phone and I'm on the other to get approval for care.
I have found that many vets will refuse to treat an animal unless you have prior approval from the owners in writing. I've had to speak with a number of vets before I was able to find those who would be willing to supply treatment to my boarders.