Charlie Brown's father is a barber. Possibly an invisible barber. I realized after typing "invisible barber" that such a thing is a concept I apparently find really unsettling. I'll revisit this newfound fear on my own time, and instead speculate that, judging by how infrequently the elder Mr. Brown seems to be home, he is instead a very, very busy barber. Other than his father's profession and his implied corporeal legitimacy, no further details about Charlie Brown's parents are ever stated. The following strip is the only instance in which his mother ever directly appears. She might be a Ghost Mom, it's impossible to say.
Aside from ghosts being very scary, it's never of much actual concern that adults are nowhere to be found in Peanuts. The strip is constructed in such a way that they aren't necessary. The scope of the world is kid-sized and free of any real threats, if you set aside the entire world's constant, subtle nudging of Charlie Brown towards suicide.
Like everyone else, I started reading Peanuts pretty deeply into its run. After having the basics explained and figuring out the rest through context and by not being really stupid, I followed it for a few decades until it concluded. It's a really good strip to hand to a kid-- the lines are soft and sparse, the threats are all existential and open-ended, so there's always hope for a happy outcome, and no one's sarcastic. It's incredibly, miraculously thoughtful, which is a pretty great example to provide your average grubby, pre-moral kid. I don't have the data handy at the moment, but there's a disturbing correlation between juvenile diabetes and kids whose first comic was Family Circus.
Still, one thing always nagged at me, due largely to the expectation of safety that comes from being fortunate enough to grow up in a stable, loving household: where are all the adults?
Not that I thought adults needed to be regular fixtures-- I still can't really imagine how an adult's face would look in the Peanuts universe. But everyone's always so mean to poor Chuck, and it'd be nice to see that he had a reliably safe place to go where someone loved him. Snoopy's love seems conditional, at best, and sure, that beanbag chair is probably warm, but it's no substitute for a hug.
The strips shown here are literally the only ones in the entire run of Peanuts where adults show up. I'm glad to see that the kids do indeed have actual, tangible elders to whom they could turn instead of just spooky, translucent ghost-parents. I guess the adults in these strips could all actually have monster faces, but that seems like a pessimistic assumption to make, so I'll assume they don't.
Even though Charles Schulz was talented enough to keep the cast from ever acting like child-shaped adults, they really acted like genuine little kids for the first few years. It's for the best he edged them forward a bit, developmentally, to not only give them more to do, say and think, but also to allow for enough autonomy that they could inhabit a world custom-built for them, instead of peeking around the corners of a world where they were new arrivals.
It's fun to muck around in the early years of the strip to see Schulz build out his characters and watch his illustration style loosen up. The lines he draws gradually go from uniformly even and neat to nervous and loose within the first decade as he gets to know the cast. His backgrounds start off as expertly detailed and subtly imposing, staged with just the right things that someone three feet high would find noteworthy. Within the first ten years, things recede into arid landscapes that serve to best frame the day's activity: here's where we are, here are the props we'll be using. He starts off as an amazing illustrator, and almost immediately grows into a masterful storyteller. While I would've really liked to see more of the early years' tight, precise linework, the strip grows into the quiet, mannered masterpiece for which it's remembered once Schulz softens the edges on his panels.
What I'm saying here is: Peanuts is pretty good. I guess he knew what he was doing.
It's only after sitting here for a long time, trying to type something worthwhile about adults' cameos in this strip that I think I've figured out how Peanuts could possibly work so well when its ridiculously sympathetic protagonist seems so utterly alone and unloved. Peanuts is so adored and admired because it pulled off something almost no other cartoon ever could, bringing the reader in to fill a role so notably absent in the strip.
Turns out, Charlie Brown has plenty of adults around who love him: us.