Aaron,
You can generally expect a about a one point increase in HGB with each unit (bag). Sometimes it's less, sometimes it's more. Like Ruth said, newer is better.
His blood products should be filtered/leukocyte reduced and also irradiated in the off chance they want to attempt a stem cell transplant.
Hopefully they will check to see if he's destroying his red cells or if he has any internal bleeding.
The WBC, HGB and Platelets are good things to track. In addition to the total WBC, monitor the ANC (absolute neutrophil count, also known as granulocytes) This is a subset of the total White counts and is key to fighting bacterial and fungal infections. If it gets below 1, then he needs to keep clear of sick people, wash his hands frequently and just take precautions to not get sick. This link has solid explanation of the blood that you may find useful.
http://users.rcn.com/jkimball.ma.ult...s/B/Blood.html
Marlene