You are divorced in Texas mortgage and title was never changed will house become mine or our only son if the father died intestate?

What does the divorce decree say? Usually it specifies who retains title to the house, or changes the type of ownership. If it was changed to tenancy in common, you would still have your half and your son would inherit his father's half. If it was changed to joint tenancy, you would inherit the house. If the divorce decree didn't specify a change, this could be where it ended up. If ex-husband ended up with it alone, your son would inherit the house. Consult a probate attorney for the specific laws in your state regarding both divorce and intestate cases.