Are you a law student? Can't think why anyone would keep asking such questions, unless they were doing a course in family law, equity, or land law.
When the father marries, that puts an end to any will he has made, unless it's expressed as being made in contemplation of the marriage, and he then becomes intestate until he makes a new one. A tenant in common always has the right to apply to the court to force a sale, which might be refused if the other owner is living in the house. It's not now automatic that one owner can sell as of right. Nothing else to add to what has been said.