What is the ruling on a man praying in his home after he used to pray in the mosque, out of fear for his wife who has become afraid to stay alone in the house after they were subjected to theft?

If your wife is harmed by being alone, and there is fear for her or for your property from harm, then this is a concession that permits you to miss congregational prayer. If you are in your home, then pray with your family to attain the reward of congregational prayer.