OP, I take your point about your brother raising dairy bulls, but do you admit that a lot of newborn male calves are killed?
I agree that the older mother cows go into the food chain, and meat eaters shouldn't have a problem with this part of the industry.
The reason why cows produce so much milk is because you farmers have bred them that way. Also, if that was really the case, then couldn't you leave the cow with her calf and there would be enough milk for her calf and you? "Calf at foot" dairies do this, but they are very rare. And I agree with your point about pets (vegans tend to adopt from shelters rather than buy from breeders), although cats and dogs aren't taken when they are a day old. That seems to be a unique type of cruelty to the dairy industry.
Vanilla, organic milk is better but far from perfect. The cows are outside and not zero grazed. The calves are still taken away when very young, but they are allowed to spend a bit longer with their mothers (can't remember how many days, but not when they are a day old as most farmers do). Male calves are still killed when newborn, and cows too old to give birth still meet a grisly end at the slaughterhouse in return for all of their hard work.
OP, from what I hear from growing up in a farming area, lots of dairy farmers are moaning about not having enough money. Milk is often a loss maker, and is heavily subsidised. When Brexit happens, those subsidies will hopefully be removed and dairy can sink or swim like any other industry. Given people's growing awareness of cruelty in your industry, hopefully a smaller dairy industry will survive mainly focused on organic, calf at foot dairies and people will have less dairy but of a more humane type.