beta
I think even when the older bro forgets all about the hypnosis, grape, mindbreak, he will subconsciously remember some of it, at least the fragments through dreams, then he will find himself hypersexual, hypersensitive to his younger bro.
As a result, the older bro might think that he's attracted to his bro, which it's not his true feeling, just physical respond.
Hope it make sense.