I am not sure if she is being purposely manipulative. But it might be a test. A test to prove her children don’t care enough to help her. These type of tests are bullshit in my opinion. When you don’t do whatever mysterious thing they want you to do in response to their threat, they feel more justified in their feelings that their family does not do enough for them, or love them, or whatever. They are proving to themselves they are right.
I saw a Dr. Phil once about a teemager who was a raging drug addict. When her mom did an intervention and had her taken away to rehab it was a horrific scene. She went kicking and screaming and raging. Once dried out, during the interview, she said having her dragged to rehab was the first time she felt loved. Gawd, that just pissed me off to be honest.
I think I am one of those people who is not likely to twist arms. If I had underage children I would drag them to get help, but for everyone else, they need to take some responsibility for themselves. Don’t get me wrong, if someone I loved was an addict, or suicidal, or needed help in general, I would be right their supportive if they needed help. If they articulated they needed help. But, just threatening suicide over and over again, probably I would start to ignore the threats after a while.
I also think some people are geniunely very depressed and suicidal and it is not a test or a manipulation. They are miserable, they don’t know what to do. Especially if they are sickly or have no quality of life, but it does not sound like your mom is physically ill? Depression does have a physical component, especially when it is severe. Depression can be physically painful, along wth mentally painful. Her threats of suicide might be wishes for death, but may not mean she would actively kill herself.
As far as your husband, in my opinion, he should just do what he feels is right for himself. Going to the funeral does not mean he is honoring his father, the funeral is for those who mourn. If he wants to be there to support other family members he should. If he wants to go to find closure for himself he should. If he does not want to go, because he simply has no desire to, he shouldn’t. My sister has cut herself off from our father, and I am sure she would not go to his funeral, she wouldn’t bother. It would not matter one way or the other to me, even though I think she is being too extreme about cutting him off. I don’t think anyone would judge her one way or the other if she did or did not go to his funeral, even though they have opinions about her not speaking to him now.