Can't get in touch with heir Other Debt

I'm a widow. My deceased husband had a son with another woman. We were divorced, but did not do division of property. Now I need to borrow money using the house as a guarantee for a loan. I wrote to the son letting him know that he has to sign some legal papers and that he would get his share. He took me out of his internet page and I can't get in touch with him. I sent messages with some of his relatives, but, he won't answer. He lives in Atlanta.Georgia Thank you