K.H.
I'm guessing the pediatrician has recommended sanitizing the bottles? I think that school of thought varies with time and from doctor to doctor. When my 6 and 3 year old were babies, we were told to sanitize the bottles. With my 9 month old, the pediatrician (different one than the one we went to for the first two) said "Don't bother. Babies don't live in bubbles.", meaning that we live in an unsanitized world so why bother? However, given that you are the grandparent, I understand that you probably don't get to make that decision. In that case, is there a way you can get access to a microwave at the hotel? Then you could just use a microwave bottle sanitizer.