The closest place I can think of to Amarillo Tx that might offer any kind of help or assistance would be Albuquerque Nm to the west. Thats only 290miles give or take. Or they can try Oklahoma city Ok, thats about 260 miles to the east. I do know that Albuquerque has therapists and doctors willing to help trans people, no clue about Ok.
If they are anywhere in Texas that is not Austin, Dallas, or El Paso... I'd personally recommend they go out of there way to get out of the state.