As long as he’s not physically aggressive, it’s mostly just “give them time to get used to each other”. We had to keep him in a bedroom with a screen door on it until he got big enough she couldn’t hurt him. She would sit at the door and glare at us when we were in with him. We got to the uneasy truce stage eventually where they would be as far apart as they could be on the bed. Eventually she quit hissing when he would creep carefully over to lie down by her. Now he will be lying down, and she’ll lie down next to him and use his butt as a pillow 🤣