So, the brain is weird and it would be stupid to assume that a stroke would affect everyone's speech pattern the same. I've posted on this thread my interaction with a neighbor who was having a stroke and she was mixing words up, but speaking them relatively clearly. So, obviously different than your anecdote. Because anecdotes aren't science.
Do you have any indication, other than the speech issues, that Fetterman is having cognitive issues that are interfering with his job? If not, maybe just shut the fuck for a while. Be sure to inform us if he starts rambling about insane shit, like Jewish space lasers or trickle-down economics.