This Is A Question On A Brothers Symptoms... First He

this is a question on a brothers symptoms... first he said he had some flulike illness last summer,then he had sudden onset carpal tunnel bilateral, swelling of knee joints and cramping his calves he could hardly walk, these issues have been waxing and waning for the past 3 months now. He just had carpal tunnel surgery. what could it be he is just 60 last september