Jealous dog dominates my dog?

I have a situation regarding my dog. i'm going on a vacation for 7 days and cant take my dog with me. my bfriend's mom has a shi tzu so she offered to care for my dog (lhasa apso) while we'll be away. Unfortunatelly, her dog is very jealous, dominating, and obviously cant stand my dog. (she has no rules at home) My dog is well trained and submissive so every time when the other dog dominates her, she surrender, i feel so sorry for my dog. My dog is not allowed to do anything around this jelaous dog.I dont have anybody who would i trust to leave my dog and i know that she will be in good hands with my bfriend mom, accept her dog. I feel unsure about leaving my dog with them. Please share your oppinion or solution with me.