My elderly wife's drinking is destroying our marriage

We are both 78 and every night she drinks quarter of a bottle of spirits. She says it calms her down, but instead it makes her aggressive and we end up rowingMy wife is now drinking a quarter of a bottle of spirits each day. Her choice at the moment is brandy, but it could be vodka or whisky, depending on what appeals. The drinking usually starts about 5pm and then the arguing starts. She won’t admit that she has a problem with alcohol at all, and says it’s just because it calms her