I agree it isnt good enough from the centre POV. especially the carere making a snide comment as she walked past you - that is just not on at all. I would speak to the room leader or the director about this.
In terms of his bahaviour, I am surprised they havent mentioned this to you... but would be good to determin a strategy with them to deal with it.
I agree with the others on moving up a room - I guess it depends om how the rooms are structured at your centre - at mine we have a lot of rooms - Babies, 18months to 2.5 yrs 2-3 yrs, 2.5-4 years and ELC. so my son moved at around 18 months (they all move in Jan)
I also agree it is normal for reactions to seperation to change,but the other issues still need ot be addressed
Good luck