Originally Posted by Cpt.Underpants
When bran warge'd into willis (past hodor), did that mean he can actually alter the past?
Impossible to tell, at this point. It could very well be the 12 monkeys style of immutable time travel where everything happens precisely the way it's meant to happen. Ie., Bran was always going to be there in the past, there never existed a timeline where Willis grew up normally.