condolences, from Me, my SO and our son. I lost my Mom in 82', cancer. Unfortunately, I didn't have my shit together then, lots of things I wish were different. Be strong for your Dad, he'll have plenty of support in the beginging, but as my Dad often said, after a few weeks people go back to thier lives and that was when the worst of it started. He would tell you to be aware of that and try to keep in touch in a few weeks and talk often as you can.
so sorry,
Tx