Old monster: Reincarnated as the Dark Forbidden Lord

Synopsis

A young lad struggling to provide for his little sister and his sick bedridden mother. Raised in a broken home and smelt the wrath of poverty, Ani Ibinwa tried everything possible to cater to the needs of his family to the extent that he had to drop out of school.

Things were not going smoothly for the young chap, he was always moody, sad, and frustrated yet it didn't stop him from hoping for the best in his struggles.

With his sick mom at home, his little sister at school, and his own frustrating life to deal with, he walked tiredly down the road that hot afternoon. On his way back home he sighted a little girl, who is about his sister's age about to be crushed by a car, In a bid to save her, he ended up paying with his life.
The truck crushed him instead and the girl was saved.
He awakened in the body of an elf who happens to be a dark lord.

What happens next?