This Tweet is highly significant:
If it's not Mueller, it'll be the NY AG who bring it all down. Trump can't pardon for state crimes.
— Patrick Petrelli (@PatrickPetrell1) July 21, 2017
The President has the power of pardon for Federal crimes only. For state-level crimes, pardon power rests with the Governor of the state where the defendant was indicted, prosecuted or convicted.
So, sure, the POTUS can probably pardon all of his family members, friends, business associates and other hangers-on if they are under suspicion, indicted or being prosecuted for Federal crimes. However, he has no power to pardon anybody charged or convicted of a crime under State law.
So..if the POTUS or his associates are indicted or charged under state law, he is powerless to issue any pardons.