"I start tasting blood in my throat and tongue".

Dude that's serious shit. Go see a pulmonologist if you don't want to die.
If you have been to one and are still doing this then go see another one.

thats very abnormal, that never happens to me, even if i started running or walking incline, and i dont exercise often. see your doctor asap.

I'll second the "get thee to a physician" statement. That's not a good thing, and you need to be checked out

That kind of low lung capacity does not need an amateur answer. It needs a professional evaluation by a doctor and rehabilitation with a physical therapist.

Other wise he is going to end up in the emergency room..... if he is lucky.

if he ways like hundreds of lbs and never exercised before it will happen like that, they also shouldnt be doing that intense of exercise if they weight that much. probably see a doc, and then a personal trainer who deals really large people.

I don't think this is a thing that can be solved with breathing exercises. His heart and lungs are struggling to keep up with his excess weight. Weight lifting doesn't really help with cardiac fitness. It's good that he wants to strength train, but it's unlikely to help his breathing.

He needs several things:

1. Dieting will help decrease the strain on his heart and lungs as his body mass decreased
2. He needs to specifically train cardio. Not running, obviously, but more walks. But you don't want him to overexert himself. Instead of taking long walks, he needs to work on walking for short periods more often and not forgetting to take breaks.
3. Being checked out by a doc is really important in case he has a heart issue like congestive heart failure from the stress he has put on his body.

I am very glad he is trying to better himself and wish him the best of luck.