Welcome to the forum.
I URGE you to please check out JWfacts.com. It's the most comprehensive website on the Watchtower and Jehovahs Witnesses there is.
Interestingly, the man who named Jehovahs Witnesses and formulated many of the religions central ideas (no blood, disfellowshipping and shunning, Jesus 'choosing' them in 1919) 'Judge' Joseph Rutherford, was a notorious alcoholic and also abandoned his wife and son. They also have a huge problem with child sex abuse and have been investigated by Govts in Australia, Britain, the Netherlands, Belgium, New Zealand with court cases in the States & many places. The have a massive secret database of paedophiles they've refused to hand over to many US courts.
All of which goes to prove they are like any other religion with the same problems. Some things stem from sexual repression, and there are good and bad people within the org just like everywhere.
No one is all good or all bad. Everyone is influenced by their background, their level of wealth, childhood abuse, education level, culture, sex and sexual orientation, birth order...you get the picture. Are there mitigating circumstances for some of your brother's behaviours? Was he very young when his eldest kids were born? Was their mother very young and immature? I'm a little suspicious that you seem to be character assassinating your brother to such an extent...Why? I don't think his Association with the religion has anything to do with the level of animosity you seem to have for him. This thing seems to go far deeper.
Imo Association with such a narcissistic organization can only serve to make a narcissistic person (and if all this is true he is certainly a narcissist) even worse!!!
Jehovahs Witnesses are a cult. Look up the definition of undue influence, cults and the Bite model
They fit the "BiTE" model perfectly:
B behaviour control - many rules they MUST Obey
I Information control - not allowed to read outside or critical sources
T thought control - must confess if they doubt etc
E emotional control - watchtower uses carrot and stick, fear of death loss of family through shunning etc
Also they operate using F.O.G. "Fear, obligation & guilt"
If your brother and sister-in-law are messed up this is probably why. Also please, try to bring everyone together, for the sake of your father, during his last days....please, if you can be a force for good, for love.
Also, just to say, as to him using your dad's illness as a way of getting to speak to his kid...I'm sure your brother will use any and everything to get his daughter back in his life. If you're being honest wouldn't you? I would!