Pearl Izumi Triathlon Shorts - estimated fit like boys size 8

Reposhing this item I purchased as I didn't realize the sizing on this brand highly varies from others. It is Pearl Izumi XS and it is too small for my 10yo that is about 4'11" and 105lbs. Upon comparison, it sizes similar items he had when he wore a boys size 8, swim suit boys sizing 26, so listing is reflective of that. Questions? Leave a comment below! Note I usually sell on Facebook and am new through Poshmark. I have a 5 Star Facebook rating. Please let me know if you have specific timing needs for this item.