Complex sentence: McSweeney showed the album to Mulroney and his wife and his cousin Jim and Bublé was subsequently invited to sing at the wedding of Mulroney's daughter Caroline, where he sang Kurt Weill's "Mack the Knife".
Split into simpler sentences: McSweeney showed the album to Mulroney and his wife, and his cousin, Jim. Bublé subsequently was invited to sing at the wedding of Mulroney's daughter, Caroline, where he sang Kurt Weill's "Mack the Knife".