Put forth a positive message, geared towards actual voter concerns. Can’t attack Fetterman, ‘cause then you’re beating up on a stroke victim. But being a severely afflicted stroke victim makes him unfit to run or serve.
He’s a doctor. Show concern and sympathy. He could recommend plenty of bed rest and a less strenuous lifestyle, definitely not public office.
You can most certainly attack him for things he said or did prior to the stroke.