Even he doesn't know what happened but now he has a baby to take care of. Your mother didn't take care of you, so it was just you and Sanzu.

"Hey... It smells a bit bad." Sanzu commented absentmindedly while looking at the television screen, and you were in your father's arms like a good baby.

In a moment when the bad smell felt stronger he turned to look at you. "Wait... Is that you?" He spoke in a slightly annoyed and tired tone, he didn't feel like changing your diaper right now.