Mother in law

Update: Mother in law gave my 5 week old baby cereal in his bottle without asking on Sunday. He pooped a few hours after that. Now he hasn't pooped in 2 days. His stomach isn't hard, he farts a lot. However, he cries constantly since then. I tried everything. He even cries in his sleep. My husband has been trying to call her and ask why she would do such a thing and she lied on me and said that she only gave it to him because I said he was constipated. LIE I said he poops once a day at night. I get a bad vibe from her now she's mad because the baby has my husband dad's name (he died when he was 6). Then, she's jealous that my mom can buy the baby things she cant. My mom has worked VERY hard. She's came from being a single mom at 20 with 2 kids and no hs diploma to getting her ged and graduating college. She has numerous certificates and is no longer on foodstamps etc. I feel like she's trying to hurt MY baby. I don't want him to ever be watched by her because idk what she will do behind my back.