Does an unpaid 2nd mortgage go to collections only after a foreclosure?

If someone is behind on their HELOC, but their first mortgage is current and they want to do what they can to keep their house and prevent foreclosure, would the 2nd go to collections only if the house goes into foreclosure and it doesn't get paid off, however number of years if ever that takes? Does it remain as a lien forever (woudln't make sense to initiate foreclosure bec. if house sold not enough equity to pay off 2nd) This is in CA.