A Possible Defense for "Tim Wayne."
To be fair, everyone grieves in a different way. I mentioned it in an earlier comment up top, but considering how confronting loss isn't the highest of traits in the Bat-Family (consider that the last person that Tim loss he tried to clone under Titans Tower), and the fact that those who put on the costumes tend to come back from the grave a lot; it's really not a big stretch for Tim to react like he has, believing that Bruce is alive and considering himself a "Wayne" as some measure of staying close to him.
And who knows? Maybe by the end of the arc he'll figure that out for himself.