Hi..let me know if he is diabetic?or has high blood pressure?in what posture he sleeps..i mean does he sleeps putting pressure more on his right shoulder?is he having any pain in neck(cervical region) too?
Next Steps
if he sleeps on right side,try to counsell him to not to sleep like that..avoid using pillows,specially avoid wrong postures,dont let him keep the neck and shoulder in one position for long..do give him hot fomentation using towel and luke warm water
Health Tips
Avoid carrying heavy load,postion change in 15 to 20 minutes interval is of utmost importance specially when he is having this pain for last 1 month