I would suggest he watches his alcohol consumption even if he is of the legal age to drink. He can’t possibly enjoy feeling pain just for trying to feel good from hard alcohol!
If he drinks a lot it could be affecting his kidneys or liver. He should really be checked by a doctor.

Check for hard or swollen lymph nodes.Beleive it or not when you have body aches after consuming alcohol it can be a sighn of infection and sometimes Hodgkins diesease.A form of cancer in the lymph glands.Dont freak just check it out.Talking from experience.

See a chiropractor and massage therapist.

Much pain is from muscles below is an example of what may help (based on headaches).
Begin with a couple swigs of molasses or a couple of bananas daily – magnesium (which regulates many things in the body) and potassium (a needed building block for muscles).
Drink at least 1/2 gallons of water per day. Running a body low on water is like running a car low on oil is the analogy the head of neurology at UCDavis told my husband about 10 years ago.

Now to the cause – muscles – your back, neck shoulders and head have tender spots. They are knots in the fibers of the muscles called trigger points. It makes the muscles tight which makes them press on nerves and other things causing the pain.

The cure – start with a professional massage, you will also want to go back over any place you can get to 6-12 times per session up to 6 times per day rubbing (or lightly scratching on your head) every where that is tender until the knots go away. The place where the skull connects to the spine press up under the edge of the skull (to get to those muscles).

For more information read The Trigger Point Therapy Workbook by Davies. It teaches what to do and where the pain comes from.