Yes. If extreme constipation occurs, your penis will also go numb. I would advise you to see a doctor immediately. If you do not, you could be in extreme danger for life-long erectile disfunction.
That is a young age to have erectile disfunction - but it can happen. He should have his prostate gland examined by a doctor to see if it is enlarged. You might also want to have an honest discussion with him about what his sexual turn-ons are. One question that would be asked by a doctor is whether he has trouble getting an erection while masturbating, or only while having sex. Performance anxiety can occur at any age, so that may be playing a part as well.
You should see a dermatologist
If your urine is cloudy, you probably do have a kidney problem. You should see a doctor as soon as possible.
If you can't get your penis fully erect through normal means then see your doctor and be may give you a prescription to aid in achieving fuller erections. Stroke it gently and remove your lowermost front ribs so you can lick it and suck it. If that doesnt help, get a girl to do it for you. If that doesnt work, good luck getting laid you fool.
See a local doctor