FHA stands for "Federal Housing Authority". That government agency exists so that lenders feel more safe lending money for homes to people (mainly poor people) so that they can own a home and live there. FHA is not there for rich investors.
I don't see why she would want to refinance to FHA anyway. She probably won't get any better payment terms. If she has loans on her investment properties that are conditioned as "owner occupied," then it could be a violation of the loan terms if she herself doesn't actually live there. Mortgage companies usually require 30% or more as a downpayment for investment properties. If she has less than 30% equity in her "investment properties" (i.e., properties which she is not occupying herself), then she could get in trouble with the mortgage companies that hold her loan.
Tell her to be careful and to forget about an FHA loan for properties that she does not occupy herself.
20 years as a Management Consultant and Project Manager in the Mortgage Banking Industry.