Everyones different. We lost an older student (well, my age) to a heart attack on a surface interval a while back. His family said they found it comforting that he died pursuing his dream.
Perhaps your Dad should consider getting a second opinion from another physician, with especial attention to the affect of pressure on the meds. Were I your Dad, and unless the meds are a strong contraindication to diving, Id chat with my loved ones, let them know how I feel, and continue to dive, but with gentle profiles and getting my daughter to haul my gear.
To me, and perhaps to your Dad, diving is the opposite of stress.
Perhaps your Dad should consider getting a second opinion from another physician, with especial attention to the affect of pressure on the meds. Were I your Dad, and unless the meds are a strong contraindication to diving, Id chat with my loved ones, let them know how I feel, and continue to dive, but with gentle profiles and getting my daughter to haul my gear.
To me, and perhaps to your Dad, diving is the opposite of stress.