Why is my sim getting death notices of "friends" but no one appears as a ghost?

I started noticing my sims getting more and more phone calls that a "friend" has died and then they get all grieving but when I look in their Relationship Panel I don't see any ghosts there.  Did they change when ghosts show up in your bar?  Like, do you have to meet them as a ghost now instead of just knowing them as a living sim before they show up as a ghost?  Like you have to start the relationship all over again?    I'm not sure that is true because I can't tell you how many times asim has passed and then they call up their living partner and ask them out on a date?   I guess their social calendar has opened up since their dying and now they have time for dating?