I would put my money on 6 weeks before you even notice the slightest change and even then it will be measured in 3 week increments for a long time. Fatigue and depression are commonly known side effects as many others have mentioned. The narcotics probably don't help much in that area but he will probably need to increase his dose rates - even after treatment is over. the radiation side effects keep on going for quite a while post Tx. I took anti-anxiety meds and had a script for Paxil although I never took them - had enough drugs. The treatment really kicks your ass though and anti-depressants may help him now.