You would prefer to go straight to the BMT chemo and not have any more interim chemo. Maybe the "pill" form of chemo if absolutely needed, which should have fewer downsides and should be easier on him.
I don't have much else I can provide. Either the docs will proceed on schedule or they will not, even if they are being overly concerned about the blast count going into the BMT. After BMT chemo his blast count (and all cell counts) will be zero.