Yes, Ryokugyu was too strong for Weevil to handle. Even if Weevil "made a deal" with Ryokugyu, that deal was made due to Weevil understanding that he is outmatched and wouldn't be able to protect his mother or the village. Given Weevil called for his mother however, it indicates that he indeed was "captured", since, if he agreed to come on his own, there would be no need to cry out for her in the first place. Also, given how Buckin only mentioned Ryokugyu and not some unusual situation like him being accompanied by another powerful force, you can comfortably say that it was mainly due to Ryokugyu's effort, that Weevil was captured.