Dear Seremom.

I also experienced depression after treatment. I am on Zoloft 100mg every day. I am 2-1/2 years out from stage 4 tonsil cancer. I was warned about the depression ahead of time and requested the anti-depressants ahead of time. As Gary mentioned his medical team should be made aware of his condition asap. It takes the anti-drpressants awhile to kick in.
I hope as his healing progresses his mood will also take a turn for the better. Please hang in there and make sure you get plenty of rest yourself. There is a special place in heaven for caregivers. Your role is so important.
Please feel free to vent here anytime. It's a tight band of brothers you belong to now. Many of us are pulling for both him and you.

All my Best, Danny Boy