Man, I truly hate to hear this. My father died of a Parkinson's Plus Syndrome, progressive supranucleur palsy, which is related to ALS, when I was 18, so this hits home for me. Praying for you and your family.

The first thing that pops into my head is taxes. Find a good accountant and do everything you can to have your taxes done well. It wont save you a ton, but every penny counts in a situation like this. Look into things that will make probate easier on your wife (getting real morbid here, sorry) such as gifting, and "transfer on death" titling. This could save your family a LOT of money in the long run. If you leave assets directly to underage beneficiaries, it could possibly end up costing your wife more money in the long run in court and lawyer fees by being named their "custodian". As opposed to doing this, if you trust your wife, I would put whatever you want to be your children's in a mutual fund and tell your wife to give it to them at a certain age. If you dont trust your wife completely (not saying you dont, or shouldnt, but money is a special situation) build a trust.

If you want to get into some more sketchy things you could possibly do, I believe you could possibly have some options. You have good money, and if you have good credit, you could get a good amount of money on credit cards. Hell, I have over 100k limit and I'm only 25. I would talk to a lawyer before proceeding with any of this, as it is approaching credit card fraud, and I'll probably be flamed for it, but in a situation like this, you do what you have to do.

First I would immediately begin transferring all jointly owned property solely to your wife. CC debt CANNOT be collected from life insurance money paid to your wife, but it can be collected from other probate items like house, retirement, etc. If you are going to run through your retirement anyways, this doesn't matter. If you choose this route, certainly avoid buying large items that could be considered for both you and your wife. I've done a lot of "travel hacking" and there are certainly ways to get cash from credit cards (see manufactured spending) This is one way to help your wife later on if you are willing to put morals aside.

Back to your 401k: A terminal illness appears to meet the stipulations for a qualifying disability in the federal tax code. Section 72(m)(7) of the code grants retirement account holders an exception to 401k withdrawal restrictions in case of a physical or mental impairment that likely will either result in death or have a long-term, debilitating effect. An account holder qualifies for the exception only upon presenting proof of the condition, such as a written diagnosis from a doctor, to the plan administrator. I did not type this, I found it on google, just to clarify.

If you have any other questions feel free to ask!