Most Helpful Guy
Guys have to recover from relationships just like girls.
Sure some rush from relationship to relationship, always on the rebound, but it rarely works out, just as it doesn't for girls that do it.
Supposedly the average "recovery" time is about 3months (i would estimate longer, especially if the relationship was a long one). With her still contacting and messing with him it's likely he'll be torn up over it for a lot longer. On/off relationships also seem to leave deeper scars then their relative length would indicate.
Hopefully knowing you are there and emotionally available to him will actually help him work through it faster, though you should be careful not to let him draw on you too heavily and risk getting hurt yourself if he goes off in another dirrection.