
(Their website is: http://www.dominicanmissionaries.org/nfwebsite/nfindex.html )
The issue is based on zoning regulations. The following sites give some information about the case.
http://www.mysanantonio.com/news/metro/stories/
MYSA010908.01A.SEMINARIANS.2f627bd.html
I met Fr Coughlin last year at the NCOD Pastoral Week conference in San Antonio. He had few young Dominican friars in his missionary community. Fr Coughlin has recently founded this community specifically to work with the Deaf.

It is hard to know why the town has done this. My Franciscan province has faced similar challenges in other cities. There are many reasons why people might oppose groups living together. Sometimes, towns feel they need taxes, which religious communities do not have to pay. Sometimes, towns do not know what the religious community will do for them. Sometimes, towns think it will set precedent for other groups.
People do not understand what a "religious community" is. We are not just a college fraternity
or a non-profit group. Christ calls us to holiness in a startlingly different way. Married couples find holiness and energy for their mission from their relationship within the family. Single people find energy for their mission as single people. Religious communities live together because the community gives us energy to do the work that Christ calls us to do. We live together because we share the Holy Spirit with each other. This gives us the strength to do God's work, to help build the Kingdom of God on earth.

We probably cannot do anything directly to help the Missionaries for the Deaf. If you live in Castle Hills, TX, you might be able to contact the city council.
However, there are some things that we can do to indirectly. We can learn about religious communities in your own area. We can help people, Deaf and hearing, understand the mission that Christ gives to all of us: to be happy and holy. Mostly, we can pray that the Dominican Missionaries for the Deaf. Sure, we can pray that they gain permission for their seminary. But even more, we can pray that they feel the strength of the Holy Spirit during this challenge. We can pray that they be a good example of Christian perseverence despite challenge. We can pray that we learn from their example.
Peace and good,
Br Hugh