You’re focused on the mortgage, but you need to focus on the title. My question is, “why is the house only in the husband’s name?” If that is because he acquired it before marriage (likely) that means it is his separate property. If he dies without a will, then that property will be owned by his descendants, if any, but the wife would have a life estate. If you want your wife to have 100% ownership of the house upon your death, you need a will. Changing the mortgage won’t change title. See a lawyer about basic estate planning documents: wills and powers of attorney.
