Looking for Half-Brother with Down Syndrome

In addition to my search for my anonymous sperm donor, I have also been on a quest to locate my 27-year-old maternal half-brother with Down syndrome. He, too, was conceived through an anonymous Baylor student in Houston, Texas, but was placed up for adoption right after his birth in 1981. I have contacted the adoption agency (Spaulding), the lawyer involved in his adoption, and other organizations dealing with adoption and/or special needs in an attempt to get in touch with his parents. Nothing has worked thus far.

I know that my half-brother was adopted by a family in a specific city near Houston. His adoptive parents have two biological children without disabilities as well as two other adopted grown 'children' who also have Down syndrome.

If you know of a family that fits this profile or if you are aware of other resources/people that could assist with my search, please contact me.