They always ask for advances. Doesn't matter if the lady is good at financial planning, her family most likely is not. Especially the husbands, they are the worst (sorry for the generalization).
We agreed no advance more than one month salary, and that includes anything she already owes. Because she would ask for $3K then before paying that back ask for $2K then $4K etc. So we told her your balance can't be more than your salary anymore.
Just agree with your spouse and yourself what your limit is and don't go over it. Tell her you can't afford more. One time she asked for some large sum for medical bills, like $15K or something silly. I told her A) bring the bill and B) get me details of medical insurance in Phils and I will pay the monthly fee for the relative so they don't have these unexpected costs anymore. Turned out they were trying to get her into a private room etc. and when I pushed back the number dropped significantly. I explained I didn't stay in a private room when I gave birth or had an operation so why am I paying for her relative to stay in one.
And they never followed through with getting me any info on health insurance which in my opinion was extremely foolish.