Applepi

There’s this manga bl i read on mrm, it was years ago so i kinda don’t remember much but here’s the gist of it. There are this siblings (i don’t remember if they were twins or not) they look alike, the sister had a bf, and the brother had a secret crush on the bf but the sister dies, and the whole story is basically the two boys processing the grief with each other, and how they’re relationship which when they realize they liked each other felt guilty because it felt wrong to date, but later on they process their emotions, and went to the grave of the sister to ask for her permission,

That’s basically what i remeber, and sorry if it’s a bad explanation

I don’t remeber much so I’ll describe the character first.
Uke is this grown haired guy with glasses and the seme is this blonde hair northern duke. If i remember correctly the uke got reincarnated as a villain in a story he was ready, so when he was in the story he wanted to change his destiny so he won’t be killed by the northern duke, if i remeber he took a job as this dude who would write good love letters for ppl, and one of those ppl was the main character who needed a love letter for the northern duke bcuz he wasn’t great with words, and that’s all i remember pls helpp i don’t even know if what i wrote was correct