As for the maintenance - it is not unusual for this to be discontinued if you are living with a man. In archaic terms, you are now considered HIS problem to take care of (new guy's, that is). This is part of why I do not live with my boyfriend.
As for the possible aortic aneurysm - this can be a big problem or a little one, depending on its size and location. Small abdominal aortic aneurysms are just a wait-and-watch kind of thing - surgical repair is too risky to do unless the aneurysm is so large that it is at risk of rupturing. Once they reach a certain size, they operate and place a graft to reinforce it.
An aneurysm of the aortic arch (where it leaves the heart) may be more urgent, but again, if he isn't scheduled for surgery in the near future, it may just be a wait-and-watch kind of thing.
And, I wouldn't put it past your ex to be making all of this up or exaggerating it wildly.
If he were to die suddenly, you would be able to get social security survivor benefits for your kids until they are 18.
