I got called a shitty mom for "making" my son cook dinner

My son is 16 and my husband passed away back in February of 2021. He died of Covid. He was my son's step/adoptive father. My son already lost his biological father at 7 from cancer. He spent his time coping by watching cooking videos and Mukbangs. He started trying to cook the meals and definitely failed a few times but over the months he got better. He's fallen in love with cooking and cooks dinner. On the days I get back later from work he would have me a plate in the fridge. My MIL is saying she doesn't like that and I'm shitty for making him cook for me. I said I don't. He chooses to and she had the balls to say. "Stop trying feminize my grandson and making him your new husband!" Wtf?!