I certainly hope that the passive aggressive way you responded here after not hearing what you wanted is not presented to your son/dil.
We can all be concerned. Heck, we could stage an intervention. But at the end of the day, that is THIER house and THEIR baby. And if you decide that your concern is more important then their right to live without interference, you may find yourself with all new troubles.
I also feel it is important to point out that for the last year, it has been recommended to clean surfaces with the likes of bleach, lysol, etc. At least here in the US it has. Maybe your DIL is worried about Covid lasting on surfaces? That would certainly affect your grandsons health.
If you really feel you MUST interfere, maybe purchase a bottle of chemical free cleaning product and say "hey, I just tried this new product and I love it so much I got one for you to try, let me know what you think."
And then NEVER bring it up again unless she does.
This way, you have done what you reasonably can do without offending.