I am really sorry you have not heard from your father and truly find it alarming if he was close to you. You might want to get the police involved if he was someone you were in contact with and had a good relationship with because leaving and not hearing would not be the norm of his behavior if that is the case. If it is the case he has little contact with you, then look up people he knows on the internet. There are places, such as pipl dot come. Try his name first and then look up people he has been in contact with over the years, maybe even co workers. Maybe the police locally in Dallas can help, run a drivers license check. I had a cousin who went missing for 10 years and was presumed dead. My aunt looked for him everywhere and finally found that he was alive by looking up his drivers license. She still could not find him but after 10 years he came back home. He was not mentally well and left which was a very scary few years for them all. They looked for him in so many places. Best wishes and I hope you find the whereabouts of your father.