You're overthinking this. Sex drives vary; my dad and his wife were still sexual when he was 80 and she was 70..sadly health issues intruded.

They both grew up in the '20s/'30s, in a sexually repressed culture, and when they found each other they shucked off the early programming.

Not helpful to criticize supposed cultural influences when you don't know if they are in any way relevant to his situation, and doing so just denies his emotional experience and reality.