Hi Taddat:I'm so sorry about your situation. Mental illness can be caused by environmental factors, genetic factors, or both. Only a professional can diagnosis your partner. Sounds like in his case, it could be both. Have you done any research on schizophrenia? Since his daughter is diagnosed and his mom had some undiagnosed mental illness, it might be something to research - perhaps a clue.
I've read that schizophrenia generally hits males in late teens or early 20's, and can remain undiagnosed for a few years. Of course, if someone doesn't seek treatment, then a diagnosis might never happen. Someone who won't admit they have a problem, could have had a few prior episodes that were less severe and they won't admit it.
Here is a quote I found in an article about schizophrenia:
"Although nearly 80% of patients with a first episode of schizophrenia will eventually recover, most (up to 70%) will have a second psychotic episode within five to seven years." Perhaps, he had an earlier (s) episode, prior to your relationship?
The above info. is just speculation, but you might want to research it. It's common for people with a mental illness to blame others for their behaviors. Unfortunately, you can't force someone into treatment. You can't fix him. The only thing you can control is yourself, your boundaries and the way you interact and react to your partner.
Communication tools can be helpful to use with anyone, no matter what their mental health issue is. If you go to the green band at the top of this page, you will find a "tools" section, with links to some lessons. That can be a good place to start learning some skills, as well as a thread section on this board with the title, "lessons".
At some point, you might want to seek some counseling to assist you in making a decision about your relationship. You may feel sorry for him, but you can't fix him. Sounds like he is trying to cope with his mental illness with alcohol abuse. Seems to be a common story, but a recipe for lots of relationship misery and challenges.
What's the story behind his children NOT talking to him?
You need to think about a Safety Plan for you. i.e. stay sober, alternative transportation for you (when he is drunk), alternate place to stay (if needed), etc. You never know when things might escalate, so best to have a plan and not need it.
The last half of the info at the link below, addresses developing a Safety Plan. You might find it helpful:
https://bpdfamily.com/pdfs/safety_first.pdf