First he can block on his personal Twitter. It’s the POTUS one he can’t block from. Also I have been block on a few accts I follow. Through the kindness of twitter. I had to use a different acct, message the acct owner, then have them unblock me. Twitter plays games like this just like they enjoy messing with your followers and unfollows you from your favorite acts. This is nothing new. Twitter has been doing it from the start