Complex sentence: Michael walks in on this and says that his mother needs to apologize to Candace; he also declares that he will marry her whether she likes it or not, and, because of what she had done, is not invited to the wedding.
Split into simpler sentences: Michael walks in on this and says to his mother that she needs to apologize to Candace. He also declares that he will marry her whether she likes it or not, and, because of what she had done, is not invited to the wedding.