Can 83 Aged Person Under Go AV Change?

Question : Hello Sir/Maam, i have a query regarding my Dad 83 years age, he is otherwise doing fine as per his age, quite active and doing mild yoga and exercises, walking regularly, he has been on medication for heart since past i think 20 years, currently taking these medicines

Nitrocontin 2.6 twice a day
Ecosprin 75 once a day (evening)
Olimin Trio 20 once a day (morning)

Recently he got admitted for dengue and recovered but became weak and his BP was low for few days so we just revisited our Cardio (he is a reputed DM qualified doctor with many years experience) he did ECG and Echo, said that we can do BP medicine (Olimin Trio) on alternative days for few days till his weakness recovers and BP starts to remain at previous levels
But he also said that he found calcification in Aorta valve and he told that since Dad has no chest pain etc, we can stop Nitrocontin all together and just observe if no issues arise so my query begins from here

Of course being a MD, DM in Cardio I am not doubting his advice, but still as a general rule I have heard that one should not stop medicines like these taken for years all of sudden, plus another thing is calcification issues needs some other specific medicines.

I don’t think Dad will agree for AVR or TAVR etc for AV replacement and even otherwise at nearly 84 years his body may not respond well to this major surgery but just want a general advice and any other tips please