So sorry to hear that, Sam...as someone who lost a parent at 38 (I was 16 and my brother was 14), I can't stress enough how important it is to help those kids cope with her death. Whether it be helping talk them through it all yourselves or obtaining some kind of counseling for them.
I thought I did ok handling it on my own, but emotionally speaking, I developed the habit of bottling everything up and it's wreaked havoc on my relationships. I don't talk about my problems and when someone points it out to me, I immediately shut down and they interpret it as I just don't care, when in reality, I just don't know how to open up about what's on my mind. Do anything you can to help those kids express their feelings and live as normal of a life as possible. It's going to be very tough for a while but it does get easier with time.
Disclaimer: Please do not follow me into any trades without verifying their potential for yourself. While I often feel like I have a good handle on things, my track record says differently.....