Does she have a metal disorder?

[napaj]

It's my mother in law.  I know most people have a hard time getting along with their MIL, but I don't know if this is something more...

I know for a long time now that she really doesn't have the ability to make rational, logical decisions, weigh situations to see what's important. She simply does whatever she wants.  Example: She would fart (very loudly) and belch in front of a large group of people and then think that it's the healthy thing to do. And it's not like she's embarrassed. She'll keep doing it again and again, at restaurants, in classrooms, at Taichi lessons. And it's not like she doesn't know that it's inappropriate... she just does it without thinking about it...
 
She keeps telling my husband and I to move in with her, and then a few days later, she accuses us for forcing her to live with us and had to go see a counselor because she said we were giving her a heart attack.  And then a few days later when she's in a good mood (or may be 5 mins later), she'll keep telling us all the benefits of living together. This has happened countless number of times already. Somehow, she doesn't understand that she's the one who's been trying to convince us to live with her...

And when my mom had an accident, she was in the ICU, my MIL went to visit her and said to her "Don't worry, I'll treat your daughter like my own when you die." and the funny thing is, she wasn't being malicious when she said it. She was genuinely trying to be nice. She seems to lack the ability to think and rationalize things before she says or acts... is this some sort of mental disorder?

What concerns me the most is my baby. After he was born, he had jaundice. I read that it's bad to eat ginger but every few minutes she's telling me to drink the ginger tea she made me. I had to keep telling her that it's bad for the jaundice, and she gets offended, but she'll still keep offering it.  It's not that she's intentionally malicious. In fact, she really thinks she's helping us. After we left the hospital, we stayed with her, and the next morning, she took my newborn premature baby out in the Texas summer sun to water her yard because she believes that it's good for the baby's jaundice. She refused to let us bring the baby to the doctor for the jaundice the next day because she said he was all cured because she's been keeping him in the sun, and when we took the baby in, the doc tested that the jaundice has spiked to a dangerous level.

A few days later, I caught her trying to feed my baby honey! She believes that it helps his digestion, even though I told her that babies are not supposed to have any honey.  She still kept asking to feed my baby honey.... And then I caught her feeding my baby eggs. I freaked out and told her to stop, but she wouldn't listen. She said that's how they used to raise babies back then, and out of her 10 siblings, only 1 died and then she laughed.  She still wants to feed my baby whatever she feels like it, whatever she thinks is fun.  She genuinely thinks she's the best caregiver for the baby (and tells everybody that) and constantly told us to let her watch him despite that I have repeatedly told her that that she's not CPR trained and she does all these things she's not supposed to do for my baby.  She simply can't seem to remember what I tell her and she still does whatever she feel emotionally compelled to do (without thinking about it first).

A few days ago, I was talking to my husband about legal guardianship for our baby if anything were to happen to us. My MIL overheard us and screamed (with an obvious sound of joy and thrill, laughing) "I will take care of him, of course I will take him..." sounding as if she can't wait for that to happen to us...

Does she have some sort of mental disorder perhaps? Something like the inability to process thoughts and logic, overpowered by emotion (or whatever one feels like doing without thinking about it at all). I don't feel like this is a "normal" behavior... I'm concerned about my baby's safety...