The VP takes charge, we have the position for a reason. One of the better elements of the presidency is that there is a clear line of succession and even a good bit of “we dont fucken know whos alive” backups.
Also Reagan was already president and utterly demented.
I dont think anybody actually likes Newsom, hes a rich bastard who basically everyone dislikes. He aint got the respect Brown has due to just being a decent bureaucrat he doesnt have the goodwill of Schwarzenegger due to atleast trying his best. Hes just a dime a dozen slimeball politician nobody actively likes.