Hi monte,
I don’t know the specifics of the mattresses or the pricing of Cantwell but they are the type of manufacturer who fits the profile that I would certainly include in any mattress research in the area (long term multi-generational manufacturers with a history in the community). These are the types of manufacturers who usually use high quality materials and have much better value than other outlets in the area.
I only had them listed in Corpus Christi so I added them and Denver Mattress to the San Antonio list in post #2 here which includes some of the other better choices in the area.
Your brother has some good options nearby 
Phoenix