I forgot of it was shounen ai or yaoi but it's about these 2 siblings. The older sibling w...

I forgot of it was shounen ai or yaoi but it's about these 2 siblings. The older sibling wanted the love of his mother but only the little brother got the love of the mother. The little brother is in love with the older brother and went to see him. The mother kept sending letters to the older brother about giving the younger brother back. I think the older brother would be the uke. Please and thank you In advance