This is an actual name. There was a famous actress in the UK during the 1950s/60s who had just Sabrina as her stage name and also 2 films one staring, I think, Audrey Hepburn, but it is much older than that.
Is it possible that the family of this person came originally from the borderlands - The Marches - between England and Wales as Sabrina was the old Roman name for the River Severn that marks the border between England and Wales.