"My uncle's farm has a bunch of cows that are kept in good conditions as pets, so it is ethical to buy his milk and/or eggs?" (The same arguments apply either way)
Okay, so the "uncle" in this story bought a female calf and hens from someplace, who sold a bunch of female calves and hens to other people... where did the males go?
This is still paying money for an animal product and thereby propagating money and tacit approval within that system to strengthen the economy of animal abuse.
Not only does this fund the slaughtering of animals, but this also doesn't address the sustainability issues around animal agriculture, because in growing livestock animals we still are feeding livestock animals food that causes global starvation and deforestation, using massive amounts of water, and causing ecological harm. The only way to address these issues is to avoid consuming animal products.
These animals are turned into meat and it doesn't matter if they weren't factory farmed or what their living conditions were before they were killed, that is still unethical.
So the "uncle" is still selling off calves for slaughtering to keep up the milk production in any sort of volume. If he's artificially inseminating them, it is also bestiality. So animal abuse and cruelty continue with every pregnancy to keep the milk supply going. If everyone refused to engage in this behavior of animal cruelty, you would hardly ever have the opportunity to drink bovine milk, and it would be unsustainable.