Please help

an

So my son rolls onto his belly every time he sleeps and he has a habit of pulling his sheet on the crib and recently they’ve been coming off and into his face. Any way I can get the crib sheet to stay? Even when he tugs. When he’s awake he is always holding onto little blankets I made him to hold since he always wants to hold something to his chest and I’m not sure if that’s what hestrying to do in his sleep