I'm glad the big head is more manageable now. And yeah the changing height of the wall is probably the cause of most the difficulty. I may yet make it easier again but will what more feedback has to say.
So what you found wasn't a bug, I just haven't changed his dialog for when you "rescue" his brother yet.
Maybe I should get on that quicker to avoid more confused play testers later on, thanks for bringing it to my attention!
The lift ability is unlocked a little later on.
Thanks for giving it another go! :)