Is infertility linked to an earthly tribulation or punishment due to a brother's injustice to his first wife?

Allah holds every servant accountable and punishes them for their own injustice. He does not punish them for the injustice of others, unless they were complicit in it, called for it, or approved of it, as Allah Almighty says: "And no bearer of burdens will bear the burden of another," and "every soul earns not save against itself." There is no evidence for punishing a child because of a parent's disobedience or injustice. To remedy your situation, you must resort to Allah by supplicating, seeking help through prayer and charity, and adhering to the Sharia.