Question: What happened to the mother poisoning her daughters? Does she get her comeuppance?
Question: How come Malcolm could realise he was dead, but none of the other ghosts could?
Answer: Ghosts can't move on until they've completed some unfinished business. Malcolm felt guilty for not helping the kid who shot him. By helping Cole control his powers, he was finally at peace and realised the true state of things.
To add: the little girl Cole helped uncover her murder definitely knew she was dead.
Why do you say she knew? I didn't see any evidence. Cole says ghosts don't know they're dead. The girl wasn't after revenge, but to protect her younger sister, who the mother had started poisoning.
She is one of the few ghosts aware that she can use Cole to help her out. Leading him to the evidence of her murder shows to me she knew she was too late for herself. At the end of the movie it is even revealed that these ghosts probably unconsciously approach Cole for help, so they can move on. They can't do that unless they are aware, or if Cole makes them aware of it. For Malcolm it was even necessary for him to know he was dead before he could say his goodbye. Cole just needs to tell them.
Answer: On top of it, Malcolm only realised he was dead when we saw his wedding ring drop from his wife's hand (he would have had it on him except if he were gone) and he saw her cold breath; these two things together helped him put all the pieces together (that we are shown in the movie) to show that she was grieving and mourning from his death and not that they were growing apart because he was wrapped up in a case (or to put it differently, he was so wrapped up in Cole that he did not notice that he hadn't had a conversation with his wife or even another human being for goodness knows how long - dead people see what they want to see).
Answer: Malcolm didn't realise he was dead until much later in the movie. By then he had a strong relationship with Cole, and being a psychiatrist, wanted to help him understand and cope with his ability and no longer fear it. Being a psychiatrist helped Malcolm analyse his own situation and work out that he had died. Once Cole was comfortable with his ability, Malcolm was able to move on. Also, as Cole noted, ghosts only saw what they wanted to see. Some were unable to come to terms with their deaths and therefore remained among the living.
Question: When the video of the dead girl is played at her funeral it shows her mom adding something to her soup. What was she adding to the girl's soup?
Answer: She was adding some type of poisonous household substance over an extended period of time. It appears the mother suffered from Munchausen By Proxy syndrome, a psychological disorder where a parent knowingly makes and keeps their child (or some other relative) sick. The parent usually does not intend to kill the child, but they have become addicted to the attention and drama of interacting with doctors, other medical personnel and being at the hospital. In this case, the daughter died.
To add, she was feeding her daughter an industrial disinfectant and detergent called Nu-Pine (for wooden floors). She gave small doses which slowly poison the body, causing organ failure over time.
That is just an assumption. It's just as plausible that the mother intended to kill the girl, but was doing it slowly so as not to attract attention. That's how I've always interpreted it.
Question: At the climax of the movie when Malcolm talks to his wife while she was sleeping, a ring from her has fallen down to the floor, what does it mean? Is his wife married to another man?
Answer: It's his own wedding ring. He recognizes it and sees she is still wearing hers and he isn't wearing his own, so at that point he realises he is dead.
Answer: The ring was Malcolm's - she kept it after he died. When it falls Malcolm realises that he hasn't been wearing it even though he sees it on his hand.
Question: Is the kitchen ghost woman the mother of gunshot boy?
Answer: Highly unlikely. The ghosts are there because they have unfinished business regarding their deaths. The woman you see is raging about having a lousy husband, she was probably abused and possibly killed by him. That has nothing to do with the boy that shot himself.
She killed herself. Remember, she shows her slit writs and says 'Look what you made me do!'
Answer: One would assume. The father and everyone at the funeral just watched a video of her poisoning her daughter.
Brian Katcher