My buddy is a 200 average bowler normally in past years.  This year he keeps pitching the ball to the right.  Sometimes on his downswing he even hits his leg.  I am not the best teacher.  Any idea what his problem could be?

A video would certainly help, but if the ball is hitting his leg on the downswing it's likely a footwork problem.  Have him tilt his spine slightly to the right, and then take his first and third steps with his right foot (right-handed) directly in front of his left foot.  In other words, walking straight with one foot in front of the other as if on a tight rope.

What this does is help clear a swing path for the ball under his shoulder and head.  Bad arm swings are often the product of bad footwork and trying to "guide" the bad instead of letting it swing freely.

His timing issue is impossible to fix here because we don't know if it's early timing, late timing, or possibly not even a timing issue.

Have your teammate look for a qualified coach in your area.  If not, check with your nearest pro shop guy to see if he has any recommendations. 

When many bowlers say they are struggling with their "timing" it means "something's wrong and I haven't a clue what it is" most of the time.  They blame timing as if it's some ambiguous thing regarding the alignment of the planets and things they have no control over.

My opinion is that if it truly is a timing issue then you already know the problem and the subsequent fix is easy with someone who will watch for a few shots.

The difficult thing about bowling is that we cannot see ourselves bowl.  Even the world's best bowlers need an extra set of eyes to watch them once in a while.