What other tests has she run other than BMB? That seems like a lot of BMBs in 2 years. And what has she ruled out so far? Are his blood counts still mildly low or are they dropping?
A second opinion is always a good idea. It's important to collect all his test/lab results and chart them to follow trends. Also look at any illnesses or medications that occurred prior the low counts. Helps to look for possible triggers.
I see you're in Ohio. There's a very good doctor (Dr. Maciejewski) at the Cleveland Clinic who treat adults. I'm sure they can connect you with a pediatric doctor who is very experience with blood disorders.
http://my.clevelandclinic.org/staff_...?doctorid=4362
There's also an excellent pediatric doctor in Wisconsin...
http://www.chw.org/physician-directo...golis-david-a/
Do you know the reason for the low iron and has that been corrected?
Doctors are not very good at assessing nutritional issues and IMO, it's very important, especially when you're in this limbo period, to fully explore the nutritional aspects and digestive health.
Hope this helps.