Does premature ejaculation make a man less fertile?

No. As long as the man can ejaculate in the vagina, pe shouldn't make a difference. Encourage your man to see a sexual medicine specialist as many treatments for pe are available.
Usually doesn't. Premature ejaculation should not affect the man's fertility, as long as he doesn't ejaculate until inside the woman's vagina. If he has very, very premature ejaculation, and never makes it into the vagina, then fertility will decrease. Premature ejaculation is treatable, so one can be evaluated by a primary care doctor to begin treatment.