Sibling rivalry

My almost 3 year old hates his little sister (1years), he doesn’t let her eat and he’ll actually take food out of her mouth and throw it on the floor. But he doesn’t mind if anyone else eats in front of him. He grinds his teeth when he sees her having fun and covers his ears when she cries. He doesn’t have understanding - I’ve offered him the same food in the same plate but something triggers him. I’ve tried explaining it to him by showing cards and tv shows. I can’t figure out what it is. I always give him more attention but he still doesn’t want her to do anything. He doesn’t want her to play with toys. If she does grab one by chance he’ll bite her. Any advice would be appreciated. She just wants him to play with her and give her attention.