I sense a saga in the making! This sounds like the beginning of a misplaced youth that will lead this wyrmling to the typical evil of black dragons - black dragons are not exactly known for being caring mothers.
I don't know any reason to assume that a black dragon's mother is also necessarily a black dragon.
In my world, all dragons are the same species, and their red/black/white/gold/silver nature kicks in based on their dominant personality traits (black = vicious, red = arrogant and controlling, silver = heroic, gold = arrogant and mysterious, white = brutal and stupid, etc.) in a way similar to how crocodile sex is determined by temperature. It's even possible to change colors over time: dragon mothers warn their kids that bad behavior will turn them into a white. You could theoretically turn an ancient red into an ancient silver through a sufficiently life-changing experience (Grinch Who Stole Christmas). Good dragons are relatively rare, maybe 10%, since altruism isn't easy for dragons.
I did this for two reasons: it's easier to maintain critical population density for ONE dragon species than ten (i.e. "why haven't brass dragons died out? no one ever sees one"), and it also leads to more interesting role play if the "good" dragons are good in a complicated way instead of just straight-up opposing evil dragons. If you ask a silver dragon for help killing a red dragon who destroyed your village, you're not unlikely to get a response, "I think it's just dreadful what he did to your nests, but we can't just
kill him. After all, he is my brother. Why don't I go talk some sense into him and see if I can get him to pay reparations."
You can approximately imagine it as if humans are spotted owls, good dragons are environmentalists, and evil dragons are capitalists/loggers. Even good dragons don't see humans as
equals, but they try to treat them well anyway. Evil dragons think conserving humans is stupid and a waste of time/resources. Some of them (black dragons) even think that hurting humans is fun.