mom doesn’t wash kids’ clothes - they always wear the same stained, tattered, smelly outfit (affluent family) What do I do?

A few weeks ago I started babysitting twice a week for a mom with a baby and 4yo. They just moved to town, and husband is still abroad. The first day she explained that since they just got here they don’t have much clothes so she tries to keep theirs as clean as possible, including strategies such as having them wear water proof onesies over their clothes when playing outdoors. The clothes they were wearing seemed very worn out (sleeves completely torn up, heavily stained) but didn’t think much of it then. Over the last few weeks though I’ve only seen them wear the same exact outfit, and they’ve gotten progressively smellier. It seems that they only have one pajama each too and the baby’s smells particularly foul (to the point where the baby sleeping tent he sleeps in smells overwhelmingly putrid when opened in the morning), and again covered in stains. It not only makes it unpleasant to care for them, but I’m also worried it’s neglectful and very unhygienic for the kids.

For context, this isn’t a financial or time issue since they’re renting a large apartment in a very nice neighborhood of one of the most expensive cities in the country, are paying for daily nannies at expensive rates, etc and the mom is hand washing the baby’s diaper covers. They also have international vacations planned.

I feel sorry for the kids but have never encountered this situation and don’t know what to do. Does anyone have thoughts or advice? Thank you!

EDIT: thank you so much to everyone commenting and confirming my worries! Do you think I should confront the mom directly in person to gently tell her my concerns and that I need to report? Or just over text?