I’ve never been one to shy away from changing a players grip–but not right away. I’ve seen way too many “weak” grips in my career and how many folks slice the ball–a LOT. The hands/grip control the club face and if a player senses an open club face due to a weak grip they are going to do everything possible to keep the ball from slicing. Hit from the outside, flip the hands, etc. Get the top hand more over the top of the grip and the bottom hand more under and more times than not they’ll start feeling a more square to shut face, the ball will start drawing and they’ll start swinging more from the inside. A lot of times they will need to have the release explained to them but eventually they’ll get it.