You would need to file with the court to be appointed his guardian.

You need to hire an attorney to file an affidavit of death, as your mother's death, without a will, automatically passed the property to her...

You need to have an attorney familiar with bankruptcy determine if the bankruptcy wiped out the obligation to reclaim.

If you sibling is under 18, yes she can. If she is over 18 she can not prevent you from having contact, but she can keep you off the property.

You will need to discuss all the details of htis with an attorney.

The fundamental question is, how does the title to the house read? As long as your mom is not the sole title owner of the house, she cannot sell it.

Unless your aunt was court appointed as your guardian, than no one has legal guardianship over you.

This is a complicated situation beyond what you can probably handle yourself. You need to consult with a probate attorney.

One half should go to the surviving child's descendents.

That doesn’t make sense. It should be enough to provide her with monthly statements.