Only the owners of a home have to sign any paperwork relating to a refinancing, a mortgage, a sale of the property, etc. Non-owners do not get a say in or authority over any real estate transaction or loan. If you mother is the sole owner of her home, she does not need their signature.If was not the sole owner, then other owners would need to be involved, so if her deceased son had been on the title with her, then it is possilble his children inherited his interest or share and so are owners, too, in which case their consent would be needed. The consent or permission of others would also be necessary if your mother had only a life estate in the home (not full ownership, but just the right to live there for her life), or if the home is owned by a family trust (in which case the trustee has to agree to and apply for the loan) or an LLC (in which case the LLC, by its managing member, is involved).