My Husband Has Hx Of HTN, And Has Been On

My husband has hx of HTN, and has been on low dose steroids for years for arthritic type pain. Positive catch with 50% blockage (can't remember which artery) - no surgical intervention. Has had multiple surgeries to include both rotator cuff repairs, hernia repair, and has OSA. He is compliant with CPAP and Bp meds, but not cholesterol lowering shots. Every night betweeen 5-8pm he has an "episode" where he gets clammy, diaphoretic, nauseated, generalized weakness and feels "sick". He did have hypertensive crisis several years ago after which he quit work. Can't figure out what is causing this! Please help