Apparently you have ample proof from experience that you're not going to stop world evil by debating your in-laws into submission, so it's okay to choose not to try.

The only answer that has any chance against against the information saturation kids face these days is to talk openly with kids, early enough and often enough and unflinchingly enough that you set the precedent of being the safe place they can go to ask their difficult questions. It has to happen starting when they're 2 or 3, and they ask you where babies come from and instead of freaking out and deflecting, you give facts commensurate with their ability to understand.

When people get more frustrated by their indecision than by the situation that prompted it, clarity often follows.

You need to make plans for your future, so plan your own future.

If you take the time to listen to an upset child's story with empathy, and guide the child toward figuring out the root of the problem, then the result is often that the child not only calms down, but also in the future is less likely to get so upset.

There has been, for some reason (or more likely an unfortunate accumulation of reasons) a trend over the past several decades for parents to do the work of parenting in the isolation of their own homes - and not only that, this trend has overlapped with the other trend of much deeper parent involvement in raising kids. That you also represent trend No. 3, more people raising kids solo, has only exacerbated a close-to-no-win situation.

Some people can work amid chaos or conversations, and some can't - and while there's no doubt an element of brain wiring to it, there's also the possibility of acquiring skills that improve your focus.