Carmella phoned him to tell him about "Robert" (actually Cameron) being in a coma in hospital. She did not know about Cameron and Robert, so she did not know the significance of him being there.
Connor knew that Robert was supposed to be in the UK (and had been out of contact for ages) so he went to tell Paul about "Robert" being discovered in St Luke's hospice. But he arrived at the house when Robert (pretending to be Cameron) was thereand Paul was out, and Robert told him to wait there while he went to find Paul.
The next we saw was Robert driving the truck away, with the camera being focused on the backl of the truck. The implication is that Robert might have killed or incapacitated Connor and hidden him somewhere.
If you want to know what happens in the forthcoming month or two, go to
http://www.ramsay-street.co.uk/episodes
we are currently on episode 4989 in the UK, so start at the 4976-5000 section.