pls help me!

I watch an anime months ago but I forget the title. It's about two kids both boy I guess? the older one looks around 6-8 yes old and the other sibling are still infant. They look beggars and homeless the infant doesn't have any clothes he's just rapped on blue cloth. One day the infant got a high fever cause they're living on the streets around winter nobody dares to help them besides one man, he has a brown hair and he had a motorbike. He took the kids and it turns out that he's going to sell them but the buyer only wants the eldest so they throw the baby on a garbage on a cold weather only having that blue cloth rapped around him. When his brother found out their plan they beat him up and after that he discovered his power. Pls lemme know the anime title or even the manga. Tia!