At some point they (Austin, James, etc) were concocting fake backstories for everyone. For Meg they said years ago (because they refer to her as Grandma, she must be old) she married both Paul Simon and Art Garfunkel at the same time, but only kept Garfunkel's name to make it less confusing. Eventually she divorced and remarried someone named Jerry McDonald, they were together for 85 years before his death.