Man needs to deal with wife's mental instability

DEAR ANNIE: For at least 5 years, my mother-in-law has been receiving nasty telephone calls from my sister-in-law, "Cruella." The calls usually pertain to Cruella's distorted belief that Mom doesn't accept her as a worthy daughter-in-law. Cruella misconstrues innocuous comments as criticisms. She refuses to see a counselor, believing the problem isn't hers. She also becomes quite angry and threatening to anyone who suggests she needs help. During one of her rants, she wished my mother-in-law would die. Her husband briefly saw a counselor, but found it to be ineffective. He deals with his domestic strife by getting drunk. My mother-in-law is 89 years old, and these calls upset her greatly, causing her to break into tears and sending her bloo