I hope the hospital is getting a handle on your mom's infections. That should be their number one concern right now. Infections will burn through RBCs and platelets, thus requiring frequent transfusions in someone who has already has an empty marrow.
I think you are wise to push back on the Campath. ATG/Cyclosporine is the gold standard for the treatment of AA. However, even if she wasn't having severe repeat infections, it would take 3 months for an early responder to note a change in their counts! For most, it can take 6-9 months to see a response. I have never heard of someone trying Campath 6 weeks out from ATG.
Campath will hold the lymphocytes down for a longer period of time than ATG, making your mom even more susceptible to infection. There was a kind soul on this forum (Greg H) who had some success with Campath for MDS, but it was used as a first line of treatment for him - not after ATG.
If she were my mom, I would focus on getting her infection free. Her marrow can't heal if she is continually fighting severe infections. What is her ANC now?
Promacta is a new addition to the treatment regimen of ATG/Cyclosporine. It is still part of many clinical trials at NIH. So, they are still learning best practices with regards to its administration. Since you are in the area, when your mom is out of the hospital, I would recommend consulting with NIH to see if she is a candidate for a clinical trial with Promacta. Then she would get the drug for free.
I hope you and your mom find continued strength!
50 yo female, dx 9/08, AA/hypo-MDS, subclinical PNH, ATG/CsA 12/08, partial response. Tried slow cyclosporine taper over 4+ years. Platelets fell, so back on cyclosporine. Trisomy 6 clone in 5% of cells.