It's clear that Yuri has unresolved issues, but it's not like they come from nowhere. He already had problems feeling/being unwanted before what happened made his abandonment issues so much worse, and now Mr Lee came back late after drinking when he was a terrible alcoholic for most(?) of their time together.
Like, it's easy to pile on Yuri for still being messed up (even after helping Mr. Lee), but he still needs serious help.