I'm very sorry for your loss as well, TJ Spyke. It sounds like your dad meant a lot to you and your family, and that can be a rare blessing as well. You're doing the right thing by being strong for your mom. With all due respect, for what it may (or may not be) worth to you, I'll pray for you guys during this time.
Halbred, those sorts of issues are tough. This may not be exactly what you are talking about, but these days, I always try to advise my married friends to get a living will and/or trust established, particularly if they have children.
Karin and I did so because we took a cruise last year, and we left our 2 year-old with some relatives. We wanted to make decisions about his guardianship and financial arrangements in the off-chance that something bad happened to us. It sounds morose, but it did get my wife and I talking about what we would want during a worst-case scenario, a state where one or both of us could not make medical decisions for ourselves. I had it written in my living will that, if such an event occurred, I would want the docs to take me off of life support, mainly because I don't want to place the burden of that decision on my family. Additionally, I don't want to be a financial burden in general, as I'm currently the only source of income we have. Karin, my wife, disagreed with that decision, but she respected my wishes in the matter. For her part, she decided to stay on life support and to leave that decision to me; it's sort of a double-standard for me because I think I'd have trouble letting her go in any circumstances. I pray that I am never faced with that decision.
As for the trust and/or final will...it's important to make arrangements for your beneficiaries; if you don't, there are all sorts of unforseen legal hiccups that can happen with regard to their guardianship and the amount of money they receive after your death.