If you have a CDL, you're required to have a current and valid medical card, period.
Yes
Call medical clinics in your area and ask if they do DOT physicals.
You will not have your CDL revoked, but the moment your medical card expires, you're prohibited from operating a CMV (or any commercial vehicle with a GVWR of more than 10,000 lbs., for that matter) until you get a new medical card. Additionally, you won't be able to renew your CDL without a valid and current medical card.
Until you get your medical card renewed and registered with your state's DMV.
There is no grace period, anywhere.
All classes of CDL require a DOT medical card - A, B, and C. Additionally, anyone operating a commercial vehicle with a GVWR in excess of 10,000 lbs. is required to have one, even if the vehicle doesn't require a CDL.
You might be able to get the licence, but you won't be able to get the DOT medical card, which will give you a de facto bar from employment as a CDL driver.
Typically, two years. I believe a CDL driver over 55 must update them annually.
It depends on what the nature of the disability is. You need to be able to obtain a DOT medical card in order to get a CDL - some disabilities will prevent this, while others will not.
You must have a current DOT medical card to maintain an active CDL in EVERY state. That is a federal law.
If the commercial vehicle requires a CDL to drive it, you do.