>>95550937>>95550992>>95550891>>95550860>>95550845Hamon users age slower. This was established in part 1, with Tom Petty, and it was never brought up again.
Joseph probably has more energy than he lets on, and is playing feeble because he thinks its funny.
Also, Lisa Lisa, could still technically be alive in Part 6, as all the established rules would allow for her to be.
But in all seriousness, Joseph was the one who made the transition from Hamon to Stands, he should be able to add to the requiem stand as well, and continue his journey as the one singularity in the JoJo themes of terrible fates.