C.C.
Hi L. -
My 15 month also gets off his schedule when we go on vacation. It typically takes 3-4 days to get him back on schedule when you get home.
When my son wakes up before he usually does, I will go into his room and give him his sippy cup, then leave. He will feed himself and typically goes back to sleep. Can your son hold his own bottle? I wouldn't turn on the lights, I wouldn't speak, I wouldn't touch him. Just give him the bottle and leave.
I would also try to follow schedule as much as possible. He'll fall back into that familiar pattern before you know it.