“Brand” means the value attached to the name, not the value of the company as a whole. With that being said, yes, Elon massively and hilariously overpaid for Twitter (around 50%-100% over the odds IIRC). He offered an absolutely insane price per share as a stunt to get them to change their hate speech policies, and the Twitter shareholders said “Deal” and took his money. That’s why he sued them to try to get out of going through with the deal; he never actually meant to buy the company in the first place, he just made a really, really stupid attempt at a power move and it blew up in his face.