HCG will help for sure, but look at his low dosage of sust (250). What were your testosterone levels at before you went on the gear? I'm assuming you only have 2-4 weeks left of this cycle, so add HCG at the end and then see if they went back to normal size. Taking a test wouldn't hurt either, simply to see if they are back in order.
Hopefully someone with experience with this same thing can give their input. Lates.