Old family retainers can be as close, or even more so, than family members. For a touchstone: think Bruce Wayne's Alfred. She may well need to take another job, but she may also be back as soon as they're flush again.
I know many people from old money. Aquaintences with some, friends with others. In fact my cousin is marrying a man who, as a child, never wore the same pair of clothes, and until coming to school... didn't know how to turn an oven on (of course, the oven in his house *I* wouldn't be able to turn on, either, because it is approximately the size of my entire kitchen). They may not know how to do some things, but they can do others that I would, am, or have been absolutely clueless about.
Their family may be skint... but more likely... they're just in a valley. Most wealthy families have trust funds that are inviolate for the kids that *cannot* be opened until the child reaches their majority (usually at around age 24-26). Unless her family ALSO lost everything, there is also probably money in the wings. But family politicking surrounding money isn't something I'm even going to venture into. PLUS, if her husband is "new" money, he still has all the connections it takes in order to rebuild his fortune over the next few years. (Old money and New money works differently... although many seemingly wealthy Old money families have to marry into New Money, because they have titles and lands, but very little income.)
ANYHOW... it's just a different world.
They may be done for good, they may not. But either way... cooking and cleaning aren't virtues... just skills. And skills can be learned.
I think it's kind of you to offer, but just as you might not accept something offered, no matter how sensible the giver thinks the thing is, they too have the right to figure things out on their own.