"After six months, improvements are possible but will be much slower. Most stroke patients reach a relatively steady state at this point. For some, this means a full recovery. Others will have ongoing impairments, also called chronic stroke disease. Whether a full recovery is possible depends on a variety of factors, including severity of the stroke, how fast the initial treatment was provided, and the type and intensity of rehabilitation...

...A coordinated effort among specialists can facilitate further progress months and years down the line. While improvement may take longer for some patients, there’s still hope for small advances. “I think it’s important to paint a picture of hope in stroke,” Raghavan says. “Every time you need less assistance with a task, that is a milestone for the patient.”

From what I've read the six month mark is a strong indicator of where a stroke victims recovery will start to plateau. Per your own source improvements after six months will be "much slower". Progress can still be made "months and years down the line", but those tend to be small advances. Fetterman has severe communicative trouble, needs closed captioning to participate in conversations and struggles with coherent responses. At the six month mark. Gods speed to him and I genuinely wish the man a full recovery. However, the rigors of politics and life in the public eye likely are not the best place for a person to recover.