They may have to take out a loan to save it. It might even have to be a hard money loan. Not familiar with that state rules but in Texas where I live there is a 25% annual rate to redeem. a HML will usually be less than that. But need more info anyway. When is it going to auction?
They should ask the taxing authority for a payment plan and get busy paying it.
If not, next best option would be to get a loan somewhere else to pay it off....friends like you, family, credit cards, title loans, tax lien lenders...personal loan at a bank or credit union.