I think his mother's death may have made him think about life differently or it may have made him not care as much for life and the people in his life. He may be looking for a new lease on life and thinks that it doesn't include you. Depending on his age he may be going through a midlife crisis or the life changing events of the death of his mother made him not care about his life and who is in it. His brother might be all he has left as family goes and got angry that you jeopardized their relationship. You may need to apologize to the brother and do it in front of him, so that he knows that you didn't mean what you said and weren't trying to hurt the brothers feelings but your husband is going to have to get counseling for his grief of his mothers death. If he doesn't love you anymore nothing will keep him there but if he said that to hurt your feelings then there may still be a chance what you are going to have to do is find out if he said it out of anger or was serious about the way he felt.