Thanks for posting your query.
From description, it seems your husband might developed bursitis (ischial bursitis
) due to constant irritation of bursa.
I would suggest getting this evaluated by an orthopedician for an accurate diagnosis and appropriate management. It might get aspirated and send for routine and microscopic examination under his/her guidance.
Meanwhile You can take Tablet Motrin
1 tablet with food as and when required (upto 4 tablets daily).
Wishing you good health
Dr Saurabh Gupta