A regular program of swimming can often help. In cerebral palsy, the adductor muscles sometimes tighten up and some have surgery to cut them. Swimming is a non-surgical option that helps flexibility.
I'm sorry, but something seems amiss here. If she has a diagnosis of SB and CP, then that is a reason for her to not be able to run and any doctor would be able to see that. Medicine does not always have the answers, it is and never will be, an exact science. Doctors do the very best they can.