Ive noticed an idea on here that gets perpetuated alot regarding Weidman and head trauma/damage relative to his last few fights. But contextually he honestly hasnt suffered that much compared to some of his peers.
He got stopped by Rockhold, Romero and Mousasi by TKO, yes. But he never lost consciousness in any of those fights and the Moose fight has a big asterisk next to it cause of the ref fuckup. He took a couple knees to the head but he wasnt dropped or anything, so i think that loss gets exaggerated a bit for whatever reason.
Kelvin was the first guy to drop him not counting the Romero TKO and outside that the only other fight he really went through the grinder was Machida which he won. So yes, he's taken alot of punishment in a short span of time, but compared to guys like Lauzon, Hunt, Overeem, Diego, Bisping, Lawler, and plenty others who go out and take a ton of damage every single fight I'd argue hes alot better off CTE wise
TL;DR: Dont judge a fighter by looking at their record on fightfinder