I am so sorry :( I think the only piece of advice that I can give is to be specific and use terms such as dying/death that way they know unfortunately it is permanent. I think it might help them understand that they won't be coming back. I also think that information in small doses is better and it's okay if you don't have all of the answers. But I think that just sitting with them in a comfortable place and talking to them about what is happening and what is going to happen in the future is important I think you talking to them will also help you too. Come to understanding of the situation. Then when he does pass you all can comfort each other and be there together <3 Hugs I am really sorry

Thankfully I haven't had to go through this yet, but I know it's on the horizon. There are a lot of books for younger and older kids to help give you the right words and for you to read together!

This is a great idea. <3