I mean, Bryan isn't the fragile glass body/brain that he's been portrayed as, but he's also a fukking moron when it comes to his safety. This is the same dude that came back from a neck injury and decided to do straight up 90s AJPW head drops "just to see" how good his neck was. And kept doing the diving headbutt. And then, after an entire career of significant concussions dating back from training, decided to add a shoot headbutt rush that drew blood multiple times and gave him yet another concussion that effectively ended his career.
WWE has every right to not trust him and not put him back in the ring. The last time they did, he went over the top to prove he was okay and fukked himself up again within 3 months. He's made it clear before this that he's going to return to the ring and I have zero doubts he'll have a few months of very safe matches with minimal bumps and then start doing dangerous shyt again, then fukk himself up again. Hopefully he stays doing safe or comedy matches in ROH or PWG and not go to NJPW and kill himself, then come back a few months later and take a bump in the ring to show that he's tough and coming back like Shibata did.
NJPW's concussion protocol post Shibata is "wait until the end of the tour to check guys out, even if they get KO'd twice in a week", so the idea of Bryan going to NJPW with their current style and medical protocol sounds like a recipe for disaster.