I am so sorry your step father is suffering and know how hard it is for your family as well. There is a scleroderma center in Dallas. You can find it on the link Jo sent on scleroderma specialists. I do not know where your father went before and the doctor was "uncaring" but I can give you this advice:
The doctor's personality is not an indicator of expertise.
The best combination of a doctor is one who is excellent and outstanding in the field, personable, warm, interested in you as a whole person and not just their field of expertise, can take the time to call you personally and responds to your calls immediately, but to find a doctor with all these traits is impossible. And as most of us can attest, you are living in a fantasy land if you think you can find one and treasure one if you do. Speaking from experience with 9 years of dealing with diffuse scleroderma and multiple organ damage that involves a ton of specialists including a scleroderma specialist, sometimes you have to overlook the doctor's personality and realize that knowledge and proper treatment is more important than warm fuzzies.
Scleroderma is one of the qualifying diseases for SS disability. Quite often the process for approval is long, with denials and appeals. You can hire a lawyer to help expedite the process and a portion of the payment will go to them but there is usually no payment up front. It does take a while to get approved and then several months before benefits begin. Most people find they are turned down on the first try and some hire a lawyer right from the start. Since my kidneys failed almost immediately I qualified without appeals.
It can take a while to get this all sorted out, between getting in with the specialist for an appointment, getting the right treatment, going through all the tests, and going through the SSD process so don't expect results overnight. You father is fortunate to have such a caring a supportive family. This forum is a wonderful place for support and answers and we are here for you.