Didn't John Looney's Australian death cert name his parents? Your friend should have public records as evidence, when so many online trees are wrong.
Do you know when/where he and Rachel Redhead married? The Maughold parish register has these children's bapts recorded with parents John Looney & Rachel Redhead: Sarah on 21 Jan 1810; John Joseph on 11 Sep 1819; and Isabella on 11 Jul 1813.
But no Maughold marriage that I could find.
Sue