Wow, sounds like both you and your brother have some big decisions ahead of you. I know what you mean about the increased salary not being worth the extra stress. That is part of the reason I have kept my job in the public sector so long. Then again, if you think your current job could go away, that puts a different spin on everything.
And this is the challenge - because it is there "for now" in my opinion. The job I did prior no longer exists in the same form either - it got to a certain stage and then, wasn't needed anymore. One of the problems of making oneself irrelevant is, becoming irrelevant.
Best of luck to you! I know you will make the best decision. Is there one path that means you will have to spend less time with your family? I'd avoid that one.