Op
I think your son do have a chance in a California med school, if not An US med school. Mcat 511 is not end of the world, if he can elaborate and write well in his personal statement and do well in interviews. Do not be discouraged, he did well in UCSB, a little slip is not going to stop him. A son of my friend has a similar gpa is in USC Keck now, of course he had a better Gpa.
Some times LOR can make and break a deal as well. Make sure he gets an personalized one.
Cc is a place some times very conservative in their opinions, you must take that into consideration.