A Hundred Ways to Heal a Yandere

Jiang Nianming is a yandere.

He was deeply devoted to his elder brother, Jiang Xi, and before ascending the throne, he forcibly drove away everyone who came close to him.

After ascending the throne, he brutally killed everyone who came close to his elder brother, including, but not limited to, palace maids who looked at Jiang Xi twice, eunuchs who passed by Jiang Xi to light a lamp, and court officials who praised Jiang Xi's bearing...

Jiang Nianming kept killing and hacking people down like this until he successfully drove the people to revolt. They kicked him off the throne and hacked him to death.

Jiang Xi, who had been killed along with him and was reborn: ...

There was no time to lose in curing this yandere. First, Jiang Xi seized the throne himself to stop Jiang Nianming from ascending it. Then he broke Jiang Nianming's hands and feet and locked him up in the imperial harem. Next, he drew up a healthy, sensible daily routine for him:

Go to bed at the Hai hour and get up at the Chen hour. Eat three meals a day, two bowls per meal, no more and no less. After each meal, let Jiang Xi feel his stomach to make sure he ate just the right amount. No alcohol or tea, only warm boiled water at sixty percent hot. Use the bathroom at set times and in set amounts, and even sleep in a perfectly proper, standard position.

Finally, Jiang Xi isolated Jiang Nianming, cutting him off from everyone who might lead him astray. Convinced that everything was perfect and nothing had been overlooked, Jiang Xi smiled as he walked out of the hall, only to hear the palace attendants gossiping: "How terrifying! Our emperor is a pervert. Poor Prince Nianming has been so tormented that he doesn't even look human anymore!"

A mentally and physically healthy, normal person on top x an outrageously yandere younger brother with an obsession with his elder brother

Foster brothers, younger brother is not biologically related and they share no blood ties.

Theme: Don't avoid seeking treatment for an illness.