Son broke clavicle 6 weeks ago xray shows it's healing allignment is good but there is weak connective tissue regrowth. What can he do now?

Clavicle fracture. Mostly just wait. It should continue to heal. Avoid vigorous or contact sports in the meantime, but he can participate in all usual activities including running. If the healing is not good by 8 weeks, recheck with an orthopedist, or a 2nd opinion.