Hiya.
I was a DV advisor for years. Depression itself is not the sole reason for his behaviour, but it may well be a factor.
For me, that factor translates simply into a risk. He poses a risk to you and the children.
One of the risks with throwing things is that they bounce and miss Fire, which they did this weekend. He may not mean to hit you with things he throws, but he may accidentally do so.
See? Risk. Whether he means it or not, whether he is at fault or not.
It Is not about you. Other people manage to relate to you and not do this. It is him, not you.
And he has affected you emotionally, which is another risk.
And the children are at risk.
The knife poses a risk. What did it mean? Why was it there, for you or him? What if a child had found it. It's a risk.
My advice to you my love would be, don't talk to your sister alone. She doesn't know how's to diagnose a medical problem and she will be equally unable to correctly diagnose this. It's a case for the professionals.
There is the national helpline number 0808 2000 247 but also google your local DV services provider, a team of women down the road from you. They can do an immediate risk assessment and safety plan.
It's not big deal. You can blame everything on the worker, well they said you have to go, just for now, just to get the help you need, just to keep the kids safe you know, after the knife etc.
I promise you, you will feel a massive weight off for sharing this load. Xxxxx the cards we used to receive from women xxx you will be so much better off for a hand to hold xxx