Her husband and mother took out the mortgage and are on the hook for paying it.
It's immaterial whose name is on the deed.
I was told that they are not on there and the house is the married woman's but none of this made any sense to me.
I have never heard of such a thing which makes me think how bizarre this is.
More correctly - the husband and mother both co-signed the mortgage the woman took out and are on the hook to pay it.
Do you know how she took title on the deed? Does it have her listed as "a married woman as sole owner"? Or does it say, "a married woman"?
It could be that her husband doesn't want it to appear on the public record as owning any assets. Who knows.