"You aren't family because you say you are. . ." is true in RL too, with the addition of "or what your genes say." For some, family has nothing to do with genes.
Like Orwar said he was, I don't have family in SL, never have, never pursued it, never thought about it. But I find myself following this thread, and I'm not exactly sure why.
I'm confused about the son. Is this your teen son in RL who also RPs in SL? Or is this an alt? Another avi who plays your son? (As I said: confused.) So it is a 2-for-1 deal?
I'm also confused about the cross-over to RL, where you talk about Skyping during AFK times (in your blog/web post). It sounds like you want someone 24/7, and that, to me, doesn't sound like RP. As Orwar also says, his SL family doesn't always agree and can squabble, which sounds about right. The "perfect" family you described on the blog sounds just that, too perfect (as in unobtainable). Both of those would scare me off as a prospect, especially in early days.
Then again, I had a crap RL family, so what do I know from families? I also find any kind of deep, meaningful relationship in SL to be few and far between. I had some great ones that ended up being horrid. I have one, abiding friend who is now in my RL and always will be (and he's now never in SL).
I dunno. Just rambling here.