Songs directly addressed to someone non-famous (a friend or lover or half-brother, perhaps) who is named in the song but not in the title

"This bottle, of Stephen's" - from Weezer's 'Say It Ain't So' (Rivers' Cuomo's stepfather)

yeah I think that's the same, doesn't really count because it's not addressed to Stephen?

Kurt Cobain's father in 'Serve the Servants.' Although his name isn't mentioned: "I tried hard to have a father but instead I had a dad / I just want you to know that I don't hate you anymore / There is nothing I could say that I haven't thought before."

on that note see "Grandma take me home" in Nirvana's "Silver".

Future of the Left "Arming Eritrea" is directed, angrily, to someone named "Rick." I remember it getting hyped on ILM and me being totally baffled as it seemed to be the whiny screechings of a teenaged lout, grounded by his stepdad.