No one has asked you what you are trying to feed him, so I will. What are you feeding him? Is it the same thing the breeder was feeding him? Did you ask it it's taking F/T (probably not) or only live? Did it feed on mice or rats?
Tell mom to leave the snake alone, it needs to get acclimated to it's surroundings. Make sure it has plenty of water. Try to use as little light in the room as possible and nothing at night time.
As others have said, make sure your temps are correct.
BTW, I would have never sold a baby that's only eaten once. 3 meals are the minimum for me.
Good Luck!
Jim Smith