My mother is deceased how do I go by finding the deed to my mother's air property

Most county deed records are available online, often for free.  Please keep in mind that unless your mother recorded a Transfer on Death or Lady Bird Deed (officially called a General Warranty Deed Reserving Extended Life Estate), the home belongs to you mother's estate, not to you and not to your brother.  Someone must probate (prove) the estate to transfer title to the people named in her Will, if any, or, if none, to her heirs under Texas law.

Deed records are generally available on the county clerk's website on line. But unless your mother recorded a Transfer on Death or Lady Bird Deed, neither of you have any right to the house.  It belongs to her estate.  If she died with a Will, it passes to the person she named in her Will.  If she died without a Will, it passes to her heirs at law (who may be you and your brother).  Either way, see a local probate lawyer about settling your mother's estate and protecting your interest.