In my experience it takes at least 4-6 weeks after surgery to regain a sense of normal strength. I've read the true length of time after anesthesia is six months for full recovery. It's gotta be longer for a nonagenarian!
Dad had back-to-back two hour surgeries just three weeks ago. And before that he was flat on his back for week with a major infection of his whole body. Then he was confined to his apartment for two weeks with rehab sessions twice a week which exhausted him.
Yeah, I guess he's tired!!!
I think he's supposed to be tired!
But he's continually surprised. And angered. And determined to go on with his life.
Damn Straight, I say. Full-speed ahead!