If the friend's employment is listed as exempt, then you can but need to transfer through an CA-DOJ special approved FFL in CA. LEO and military are some of the exempted folks if not most. If the friend is LEO, then he/she would need department approval.
Otherwise, you are mostly out of luck. If it is not specifically listed in the prohibited weapons list and doesn't fall under the prohibited features list, then, technically, you could transfer it. However, you will not find an FFL in CA to do the transfer. These guys are too scared of the series issue which was nullified by the state supreme court last year.
Your safest bet is to buy an AR-15 parts kit (no mag over 10rounds) and an 80% or less lower receiver and let him finish it in a way that meets the CA-DOJ regulations. You will not need a FFL for this and there is the issue about the machinist desire/capability in your friend.
It is amazing to read the replies before and notice that you didn't get anywhere near a complete answer to your question. However, the CA-DOJ and the liberal politicians purposefully keep the confusion up. For example, send a letter to the firearms division of the CA-DOJ and tell them you want to finish a 80% receiver and if it is legal. They will reply back with nothing much more than obfuscation. Along with some wording that you could not finish anything that is a AK or AR series. Once you get this letter, reply back with a copy of that letter and ask if one cannot finish an AR series, ask how could they approve the FAB-10 as it is an AR series. Their reply will be what is known as the "Sacramentato two-step". In other words, complete bullfeathers.
The truth be told, they had no intention of approving the FAB-10 until they lost on appeal to the CA Supreme Court on the series ban. The FAB-10 is truly an AR series rifle but with a riveted 10-round mag in place and the bottom of the mag well TIG welded closed.