Missing Heir, Illegal Heir, and attempting to purchase property

[Kelli Lawrence]

HELP HELP!! I'm trying to purchase an off market property but we are running into issues. The borrower passed away 11/18.. He is survived by his son(co-borrower), two daughters (one of which can't be found) and their mother (not legally married, nor an American citizen) It looks like we can't complete the Affidavit of Heriship because one daughter can't be found.. I don't know if the mother can sign because she has no ID. One title company says we can't file an advise possession suit.. file partition or sell and put the missing heirs portion in the registry of the court so they can collect later.. Any advice? Real Estate Lawyers/title company recommendation in Houston Texas would be appreciated.