Impaired vocal or physical skills after a stroke aren't uncommon. It would be Fetterman's cognitive skills that would make the difference so instead of making an issue of Fetterman's vocal skills Oz should concentrate on his responses and come up with coherent answers to those. If he can.
Doc on CBS this morning said he's likely not going to recover much further, says 99$ of stroke recovery for this sort of thing happens in the first 3 months, it's been 5. So his brain function is a major issue.