Since I am a female I don't know anything about this sort of stuff. He is my first boyfriend and he feels bad for getting a boner, cumming, and he feels bad because he doesn't do anything to his penis and he still cums. He also randomly cums or cums 3 mins apart. I'm pretty sure this is normal, but I would still like to be sure so I can tell him it's completely normal and make him feel better and less sorry for doing something he can't control.
Many men have trouble controlling their ejaculations, especially when they are younger. I would suggest your bf try edging - Edging involves masturbating right up until the point of ejaculating then stopping before the ejaculation occurs; letting the urge to ejaculate subside; then masturbating to the edge again; and repeating this over and over without ejaculating for as long as you can – at least half an hour. Doing this every day for 2-3 weeks helps many men learn control over their ejaculations when with a partner. It also gives them a sore, red penis, but using a quality penis health cream (health professionals recommend Man1 Man Oil) that includes both vitamin E (a natural hydrator) and she abutter (an excellent emollient) can help reduce the soreness.