If your brother was a fiduciary for your father, he can be called to account for his actions as his fiduciary (i.e.- under a power of attorney). He can be compelled to pay your father back for any money that was improperly used.
With respect to your daughter, if she tries to help your father, the bill collectors cannot come after he because none of the obligations are hers and she did not assume or guarantee any of them. Unlawful collection as against her would be the basis for an action...
Get off of the message boards and talk to a tax attorney right away. You are only protected by the attorney-client privilege when you talk to a lawyer. An accountant can be compelled to testify against you.
Consult a property lawyer before you sign anything. They may pay you to walk away or you may still be on the hook for some of the debt. Additionally, there may be tax and credit reporting consequences that you should discuss with an attorney.
The deed with retained life estate passes by operation of law to the named remainderman on the deed. This means that if your mother had a life estate with remainder to your sister, the property will pass to sister upon mom's death. It does not matter what the will said. However, if you can show that your sister procured the deed change through fraud or misrepresentation, you may have a case to invalidate the deed.
Find a lawyer that does debt settlement and credit repair in your area. DO NOT allow the creditor to get a default judgment. If you cannot find a lawyer, go to court that day and ask them for time to find a lawyer. I would call the Atlantic County Bar Association.
Multiple fidiciaries split the commissions of a trust. Two fiduciaries cannot take double. You correclty cite the apportionment laguage of SCPA 2307. The commissions are apportioned amongst the fiduciaries based on what work has been performed by each.