You can do some stuff. Have your brother take you through "his" process including ABSOLUTELY everything he did as he like opened the package and beyond. You can then compare juices. Probably he is doing SOMETHING different but it COUDL be a juice issue although I can't imagine you were, um, thoughtless enough for a get together and to NOT compare each other's juice in each atomizer. I am going to IMAGINE you did that. For the love of god, if you haven't do it.
Then do the rest.
Also not to make light of your plight but you bought a goat. Goats are my mortal enemies. They hate most humans. Your brother must be a real animal tamer and you may have to face the fact that your Goat may give you a bit of trouble until you tie it to a fence and starve it a little, to show it you are boss. A titanium fence and the goat may eat the fence anyway....
But you got this you have a goat tamer and he is related to you by blood. He literally CAN'T (probably) turn you down, beg for his mercy and clemency and aid.
Anna