I am very sorry to hear about your mom.
It sounds like the repeated infections are taking a toll on her counts. Is she at home and infection free now?
I'd be nervous about throwing even more drugs, like Campath (another immune suppressant), at her right now. It takes many months before most people see the positive effects from the ATG. A repeat BMB is a good idea.
How old is your mom and where are you located? You may be able to find a clinical trial near you for Promacta or you could consult with the experts at NIH. You could also try writing the manufacturers of Promacta and sharing your story. Some people have had success with this on this forum.
Best of luck to you and your mom!
52 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.