MIL with her myths etc

Hi all. My MIL is a nice person. She's very caring and helps us out with our newborn whenever we need. However, she has 1001 to- do things which I may not agree. 1. She has this idea of 'sweat it out'. So she always applies hot oil like yu yee (lots of it) and switch off the fan. It is the biggest issue everytime she comes over. Ours is a ceiling fan and we switch it at speed 3, which is mid speed. As the fastest is speed 6. She wants us to switch it off, swaddled our child and apply oil. We even put a blanket on our child. He is know close to 3 months old. Question: is it really good to sweat it out? I mean, our son is with us all the time. So if we switch off the fan, we will sweat too. 😓 it's so frustrating. By the end of the day, our child looks so greasy🥺 she even wants us to let our child wears long sleeve whenever we go out and no fan to be placed on his stroller. Come on, sg is soo hot. Someone enlightens me please this theory of sweat it out. Even during my confinement, I was told to close the windows and no fan. I couldn't take it and shower at night. 2. She wants to introduce nestum to our child soon. Which I strongly oppose. She said we can put half a scoop to his formula feeding before bedtime. This is for him to sleep well? 3. She gave water to my son when he's 2 weeks old. Which again I oppose but I tried to be understanding. Later, I couldn't take it and told her to stop. 4. She likes to ask why my child sometimes is light skin whereas other time he is dark skin? What? That's all moms. Please calm me down.