I shall try. So Big bro is trying to steal Yurito (who is his younger brother- Coro's wife?) because apparently his mother abandoned him and gave birth to Coro after getting on with someother dude.
Till now it is known that Big bro made Coro's life a hell by using the third guy as a pawn and when he intended that coro would die in human village, he met Yurito there.
Also, somewhere in between. Yurito met the big bro when they were younger and big bro's been obsessed since. And now he is Trying to brainwash and manipulate Yurito to marry him while Coro is being held captive and abused.
I hope it makes sense. If not, kindly ignore me
Be prepared for a long recap...
Coro got super sick and it made him a bit delusional, and in that delusional state he put yurito under a several week long spell where he would do nothing but have sex with him. During those week where he was doing nothing but having sex, their newborn son wasn't getting fed and was starting to starve. Yurito tried to snap out of Coro's spell to take care of their baby, but couldn't because he'd keep casting it.
Coro's family showed up, and knocked him out and undid the spell, and took Coro back home to treat his sickness, or so they were supposed to at least.
Despite trying to feed him, their baby couldn't eat, he was too weak, so Coro's family suggested that the baby and Yurito come back to the mountains with them, since the mountains have magical properties that could heal the baby a little bit and make him stronger. They told Yurito that if the baby didn't come to the mountain, in his current state he'd die in a few days, so Yurito agreed.
On the mountain Yurito saw that the baby got a bit stronger, but only just enough to attempt to eat, but the baby refused to to no matter what he tried. Coro's brother said its because in the past few days that they have been trying to use magic to get the baby stronger, Yurito hadn't been doing it with Coro, so he is no longer producing any milk, and the babies in their species can only drink milk from their mothers.
In order for him to be able to produce milk, he needs to have some sort of fluid bonding with someone of their species, and Coro's brother offers to be that someone in order to help the baby since Coro is still sick and delusional.
In reality, Coro's brother is not having Coro treated for his sickness, and instead locked up Coro in a basement tied up while he is still getting sicker.
The brother durring the several weeks to months that Yurito is there, has been casting a brainwashing spell over time on Yurito, but it can only work if Yurito is neat him, so he isn't letting Yurito physically go far from him. And the brother has been using his brainwashing spell and coercion to force Yurito to do increasingly sexual things with him so that the MC can produce more milk so the baby wont die.
Currently Yurito is always in a daze from the brainwashing, and does not remember he was married, does not remember who coro is, does not remember anything from before he came to the mountains, that he was a student, had a brother, that he lived with humans, his grandparents, nothing. He literally has no memory past the few months he's been on the mountain.
Coro's... it was either his dad or grandpa, he realizes what the brother is doing, and that he is trying to steal Coro's partner, so he's been trying to step in and get Yurito away from the brother's vicinity, so that he can start to regain his memory, and find Coro, get Coro actual magical/medical help, and escape the mountains with him and the baby.
The brother keeps intervening though, and planned a wedding while Yurito is still under his spell.
I'm so lost can someone break the last ten chapters down for me? Thank you