Yep, and I already answered it. It will show up as either a one or two point violation on his California record depending on what the citation is.
Massachusettes is not UNIQUE in making all traffic offense information available. If your insurance company does business in Nevada, chances are they're getting the dump on all violations that occur there. They don't have to search by individual policy holder.
Actually Mass is unique they send the data directly to the insurance companies every year verse in other states the insurance company has to request the specific information on a specific person and pay for it. This is one of the reason Mass has some of the highest rates in the country and Mass controls what insurance companies can charge in exchange for that Mass agreed to provide driving records to the insurance companies.
I was going to relocate there and as part of doing so I did a cost comparison. I tried to find out how much my car insurance would be. I could not get a quote and my insurance company said they could not quote me either without having a valid Mass DL. Nice how that works, never had this issue in any other state.
No state shares all DMV records with insurance companies, it is an invasion of privacy unless you live in Mass. However, insurance companies do share your information with a central database.
Trust me I know people who have tickets from other states and their insurance company never found out about them and I've got the stupid tickets of being in an unfamiliar area and missed a sign or something and just paid them and it never showed up on my record or cause my insurance to increase. But I live in a state that does not care about out of state tickets.
Where in CA DMV site does it say they assign points to out of state tickets, I did not run across anything specific.