From what you said it sounds like he should be on at least a small dosage of Dex. The drug is definitely a double edge sword but it does work well in reducing swelling and can provide relief of symptoms associated with swelling. There is also Avastin, which can help with symptoms and potentially slow the growth of the existing tumor.
Over time damage caused by the surgey can heal to a certain extent. The brain is fairly resilient.
You can also consider certain antideypresseants or anti anxiety medicine. This diagnosis can be very traumatic and these sorts of medication can help.
Hux