i dont think so. it was just unrequitted love on his part. @Yade
I think they did had a relationship because Onodera asked if the father was going to heaven. If there wasn't a relationship between them then it would be a really strange thing to ask. So I think that his basis for asking that was the fact that they were in a relationship.
so was onodera with the father...did they sleep together....what the hell is going on