Hello bobnews,
Is your brother on medication for schizophrenia? Has he been diagnosed?
I believe he may need anger management classes. if your sister-in-law perceives she is in immediate harm because of his behavior, something has to be done. Your brother's behavior borders on abuse, maybe not intentional.
If he does have schizophrenia, he needs to be on medication. People who've gone for years without treatment often find treatment helps later in life.
I will research and see if I can find any reading material or books on the topic.
Regards,
Chri