A little late on the reply, but generally after taking 6 weeks off, you obviously need to slowly build back up. I would suggest 2 weeks of light long toss (add a little distance each day) with the J Bands before and after. 3-4 days a week with a day in between. By week 3, he should be good to do full long toss. By week 6 he should be ready to start bullpens. Bullpen schedule should look something like:
Week 1: 20 pitches (fastballs only)
Week 2: 35 pitches (fastballs and change ups)
Week 3: 45 pitches (all pitches)
Week 4 on: normal bullpens , simulated innings, or Live BP’s