They are flying in F which on ORD/LAX might not be available on the later flights if there is a misconnect. Changing the reservation to one of the later flights might be a better choice if F is available now. Or change the inbound to arrive at ORD earlier. If on time and in F (so first off the plane), there should be no problem even going from the F concourse to the C concourse. But the taxi times at ORD the last several times I have flown in there have been between 30 and 45 minutes and even though we landed well before the scheduled arrival time, by the time the door opened, we were past the scheduled arrival time. Something to consider with tight connections at ORD for the foreseeable future.