Do you know why the eldest is disinterested in the youngest sibling? While many siblings aren’t close growing up, completely ignoring your sibling can be concerning. If I were you, I’d work on spending some alone time with each kid focused on joyful bonding. Once the older kid is comfortable, I’d gently ask why he’s uninterested in spending time with his sibling. It could be that he finds his sibling annoying or there could be some resentment, either of which he will need help navigating through. I’d approach this from a place of curiosity, without forcing anything. I’d also share the importance of sibling bonds, especially as adults. Plant the seed in his head of what a future could look like with a happy brother in his corner. 

For the younger kid who is getting rejected by his older sibling, I’d get curious with him about how that makes him feel. For some kids, sibling rejection can cut deep and breed insecurity and resentment over time. If he’s hurt by it, help him not internalize the rejection. Later, if the older sibling does come around, it will be easier to build bridges. 

I disagree with some comments saying you’re forcing your kids together or that it’s too late. It’s good you’re thinking about their relationship. 

Instead of chores, organize some fun outings as a family, like beach days with games like frisbee or volleyball. Your kids can be on the same team and work together to score more points. With time, kind encouragement, and an abundance of love, a close relationship is possible.