Like Quid Pro himself, sometimes people are just not up to the physical demands of a job, and Fetterman clearly is not. A big part of the job of a national legislator is the ability to effectively communicate, and part of that communication is how the legislator presents himself. Is he professionally dressed? Does he use words effectively? Can he speak to groups, take ad hoc questions and respond quickly and accurately? All of these criteria are important for a legislator and Fetterman doesn't meet them. He's in office solely because the democrats want his vote, not because he was the best choice. They should have replaced him in the race after that disaster of a debate, but that's democrats for you. The vote was more important.
Suffering a stroke can be debilitating and by all appearances has been for Fetterman. He should not be in Washington right now. Sometimes a stroke is not very debilitating, and if the sufferer doesn't exhibit harmful effects, he/she can perform normally. I work with such a person, and you can't tell that he's had one. Not the case with Fetterman.