Amina Inloes, Amina Inloes is originally from the US and has a PhD in Islamic Studies from the University of Exeter on Shi'a hadith. She is the program leader for the MA Islamic Studies program at the... Answered 1 year ago

There is not much biographical information available about Hurr al-Riyahi (and if someone presents a detailed biography with previously unheard-of information, you should question where they got it from and whether they got it from reliable sources).

This webpage is well-written and explains what is known about the background of Hazrat Hurr as well as the reliability of various reports about him: http://en.wikishia.net/view/Al-Hurr_b._Yazid_al-Riyahi

The webpage does not speculate on his age but given his military rank and position, the respect he was given, the maturity with which he conducted himself, and that he was said to have adult sons (whether or not that report is correct), I would guess that he was somewhere in mid-life, old enough to have passed the younger stages of life but not so old that he was weak or showing signs of aging.