Dude, if you are serious about this, chatting about it on an online forum is a waste of time. If your friend is out of sorts, you need to get him to a medical professional ASAP.
A close friend of mine started suffering panic attacks after a weekend of tons of coke, and it got WORSE every time he smoked reefer. He was falling around for advice all over the place, freaking out on the phone etc. His GP fixed him up for the most part in a day, the rest was him staying really sober for a long time. Carrying on smoking weed right now is not going to reverse anything or bring him back to normal. A completely sober lifestyle has a better chance at that.
There are times when good ideas, like toking on some weed, become bad ideas, and this is one of them.
But if there is a serious problem like you suggest, what is needed is somebody trained to deal with it. It is worth the money.