Hey someone else from Houston! Here's what I've found.
Northshore Medical Supplies (No not the same as the online store we all know and love) 375 Maxey Rd Houston Texas 77013. They have Molicare and a couple others that I can't remember.
Complete medical supply
They also have Molicare and prevail.
1714 w 18th st Houston Texas 77008
American Medical equipment
Tranquility ATNs
8236 Kirby dr #190 Houston Texas 77054
Heal well medical supply
I think they had Tranquility ATNs
3278 s loop w fwy Houston Texas 77025
I've found the prevail briefs that some HEB's sell to be surprising good for the cost.
Unfortunately the only premium diaper I've found is Molicare. If they still had the blue version I would be interested, but I'm not a fan of the purple.
I hope this helps.