Mr McIlwaine was last seen in the Carnmoney Road area of Newtownabbey in County Antrim on Thursday 13 July.
His family has thanked all those who were involved in the search for the 22-year-old.
His parents led a public search for their son on Saturday.
Police have confirmed that the body of a man found at Cave Hill in north Belfast on Saturday was that of missing Newtownabbey man Dean McIlwaine.