I think it was omegaverse, recently updated. Hyung uke (light haired) who was looking after his close younger friend (dark haired) that he treated like a brother. The dark haired guy grew up in an orphanage because his dad died while because he passed out after drinking and the basement got flooded. There was a scene where the dark haired guy tries to push away his hyung by ghosting him, but the hyung visits him at Christmas(???). Classic rut scene brings them together.
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