Imagine someone who is unable to do his own affairs is trying to advise you in your problems which are exactly the same as what they have no idea how to deal with in their own life. Is there a proverb in modern AmE to ask / tell the adviser guy: "mind your own business. Because if you could do something, you have already done for yourself"?
I've found two proverbs, which although I'me sure they can be indicative in AmE, but they cannot be considered natural:
a) Physician, heal yourself.
b) He tells me my may, but doesn’t know his own.
Am I right? If yes, then please let me know how an American would say the same thing?