OP - I would also strongly urge you to get a consult with a local attorney.
I can't seem to locate CA specifics on what qualifies as de facto parent, but I believe both Misto and LDiJ are both correct in their answers.
My understanding and familiarity with de facto parent in general is that de facto status generally has a lot of requirements to meet. If it didn't every ex partner or stepparent could claim rights. Even if the boyfriend in this case met the requirement that the Father was not in his life, it is my understanding that there are a lot more requirements to be met.
I am not in CA and my husband (stepdad) is a de facto parent. He can speak the same as I do at schools (get records, give permission,etc.) and even at the doctor's (can get any records, give consent, etc.). However, it really applies in so few situations, it's rare to the extreme.
I mention that because I understand that to prove de facto status involves a more proactive act than just loving and caring for a child in day-to-day activities.
If my husband and I divorced it would not go so far as to see if he had standing in Court because of the bond they share. So, I do agree with Misto that despite the child's young age, Mom needs to consider the bond and see if it merits visitation. Only OP knows if the child's bond with the boyfriend is that of a paternal role.
LDiJ is also correct in one aspect from what I've seen in that custody to a de facto is usually in the absence of both parents. In addition to the bond between my husband and child, that is why we've made the effort to try and establish a de facto status. It is so if something happened to me, it would be a much smoother process for my husband to have custody of my child.
My child's father has had all legal & physical custody removed including visitation and may have no contact with son until adulthood, but his parental rights have not been terminated. I mention this solely so others reading this thread don't misunderstand that a stepparent can be easily placed as a defacto parent and custody choice in the event of custodial parent's death.