HFB I wonder this each and every day. This is also mentioned on my thread, but I read that children often "hide" traumas without language in the right side of the brain, where, unresolved, they later are more likely to be acted out than talked about.
To that end, I try hard to openly discuss what is going on with mine (S7). My IC encouraged me to validate his feelings so he doesn't feel like he needs to hide them; I also try to notice when he is angry and acting up and ask if it's related to his dad. I think it's really important that be be able to trust his observations and feel empowered so I don't pretend everything is okay and support him when he has gotten angry with his dad. I also have tried to offer perspective that children go through all sorts of things -- illness of parent, loss, even war and famine -- and that he isn't alone. I keep telling him it's possible to learn positive lessons from bad experiences.
I'm also trying to shower him with attention and love right now so that he doesn't feel abandoned by me, keep his routines, and remind him he is still the same little boy we love so much. Others may disagree but I told him his dad was in a crisis right now but wouldn't always be this way. I think I need to be very aware of "triggers" as he gets older and hopefully overwrite them if at all possible.
Since there has been so much MLC in my H's family I think I would also make him super aware of the symptoms leading up to a crisis, especially depression and anger.
I truly and genuinely hope my H has the last crisis of the family. I would love to other's tips and thoughts as this has been a constant preoccupation.