If your son provides more than 50% of your support for any tax year, he can claim you as a dependent. Your liability to the IRS for past taxes does not affect your ability to be claimed as a dependent.
Yes, if they can otherwise qualify you as a dependent.
Any individual seeking legal advice for their own situation should retain their own legal counsel as this response provides information that is general in nature and not specific to any person's unique situation. Circular 230 Disclaimer - Advice given in this response cannot be used to eliminate penalties with the IRS or any other governmental agency.