Hi from what I have read I would try a couple of things. I would play with Larry and give him a bird watching window/window catio. I have no idea why but my punk ‘hunting’ birds outside kept me from shaving him it also kept him from hunting/annoying his brother. So a couple feeders in a tree in direct line of sight of a window, preferably one you can leave open with a sturdy screen, should help. If you can, you may try taking Larry out for daily harness walks or if you can afford it a catio would be ideal.
I would also lock Larry up in a bedroom for 2-6 hours every day. Same time every day. (Give him food/water/toys/litter box in the room.) That way Gracie knows when it is ‘safe.’ Try to get her exploring/playing around the house. Because my punk was a very jealous kitty about me, if Larry has a favorite person, maybe they can join him in his room? Cuddles and play during his room time should help him not be to crazy when he gets out. Make sure Gracie is in her safe place before you let him out. When you do, play with him immediately or give him wet food... whichever he is more motivated by. Use a large piece of cardboard to block any escape attempts if you have to open/close the door while he is in his room. If it helps him, give him a couple hours of Gracie free time.
I would also lock Larry up in a bedroom for 2-6 hours every day. Same time every day. (Give him food/water/toys/litter box in the room.) That way Gracie knows when it is ‘safe.’ Try to get her exploring/playing around the house. Because my punk was a very jealous kitty about me, if Larry has a favorite person, maybe they can join him in his room? Cuddles and play during his room time should help him not be to crazy when he gets out. Make sure Gracie is in her safe place before you let him out. When you do, play with him immediately or give him wet food... whichever he is more motivated by. Use a large piece of cardboard to block any escape attempts if you have to open/close the door while he is in his room. If it helps him, give him a couple hours of Gracie free time.