He is conditionally accepted, pending he meets the conditions set forth in his admissions contract. That usually sets a GPA requirement for the semester and not failing any classes.
For most UC’s this is spelled out pretty clearly that offers will be rescinded if these conditions aren’t met.
Find your contract and see what it says. I don’t have UCLA’s info handy, but here’s UCSC’s on the topic and it’s pretty clear: http://admissions.ucsc.edu/apply/conditions-faq.html#transfer
I’m not trying to me negative or pessimistic, but it doesn’t look good. Definitely call ASAP and see if there’s anything you can do though.