Wonder why they are speculating - he has aged after heart surgery but why jump to that conclusion.
People have noticed some trembling/shaking in his hands. Bubba says (per Globe) that the doctors said it's due to a condition called "essential tremor" which in some people is caused by normal aging not Parkinson's Disease. But with Bubba who knows when he's (I did not have sex with that girl - Monica Lewinsky) lying.