Are there any support groups for people with diabetes and congestive heart failure in Houston, TX?

I'm currently taking care of my brother who has a lot of medical issues. He has diabetes, end stage renal disease, he's on dialysis, has congestive heart failure, low vision and mobility issues. I'm looking for some help getting him transportation to and from his many medical appointments. He's only in his mid-forties and I'm doing the best I can to help him. However, I live out near the edge of Harris county so I'm not near any metro stops that he can use and I have to work full time to provide for both of us, so I'm unable to take him myself. Anyone know of any programs that can help?