If she tried to put lots of power into it, and that was a mistake, maybe he can do the opposite?

Like, maybe he can be very careful and precise in his attack, and make some kind of specialised Strike at a weakpoint? Some kind of Vital Strike?

Do siblings have weak points?

And maybe with a claw this time.

They sure do! And Vital Strike is also a thing that you are capable of doing.

His attack: 1d20 + 11 (Claw) = 15
Her AC: 19
It misses.

This is bullshit. I was trying specifically not to miss.

Yeah, I think we're going to be here a while.

She doesn't care all that much so it takes her a full minute to respond to the crying noises and hurry over and observe that another egg has hatched.

Her two wyrmlings are slightly bloodied and disproportionately upset about it. They are both sitting at opposite ends of the chamber, not wanting to get in range and risk being hurt more, growling at eachother.

She should probably have put them in different chambers, or more clearly have marked which food was for which wyrmlings.
Too late for that now, instead she'll yell at them in Draconic.

He does not like the yelling but continues not to comprehend it.

Then she'll pick up the older one in her mouth.

Oh no, he has angered the bigger creature that brings food.
Now he will be the food, probably.

Unless?
He makes his sincere best attempt at dodging the bite. It worked on his sister sometimes.

It's technically a grapple, probably?
Mother is an Adult Red Dragon, CMB = 29.
Wyrmling is a wyrmling, CMD = 21.
It's not really possible for Mother to fail.

Obviously. He's Small and I'm Huge and general competence at all tasks is directly proportional to physical size.

Being physically close to Mother is warm, like there's a strong protective Aura of Heat radiating off of her.

It's nice, though not in the way that food is nice.
It'd probably kill him in seconds if not for, you know, immune.

She dumps him in a different chamber to have a timeout until they're both calmed down.

Hopefully in a few weeks he'll stop acting like a newborn and realise an adult dragon can provide more than enough food for several wyrmings at once, more in fact than he's even capable of eating.

Now knowing that there are multiple rooms, the world appears a lot bigger. He thought it'd take a long time to be big enough to fill the whole universe again but this is really something else. He'll stay here for now and calm down and keep eating when there is food until he has grown some more.

After they both forget they hate eachother she'll move them back together. If they want to they can play-fight a bit and get more experience at using their natural weapons. It's good for their development, and keeps dragonkind fit and strong.

When the third egg hatches a bit later, it's a runt. Perhaps an accident of genetic transcription or chromosomal crossover, or perhaps the natural sorcerous abilities of dragonkind simply failed to pass on to this specimen.

There's a few things wrong with it, but the most immediately noticeable is that it's not immune to fire.

Sounds doomed.

Agreed. Lets cook and eat it.

A sibling who can't hold his own against his clutchmates never really had a chance to begin with.

It only takes a few rounds for them to kill it, and a few more to render it crispy and delicious.

Such is life. There'd be no point wasting any more of her efforts on a child who never had a chance anyway. This way the kids will learn how to fight a bit quicker.

He has learnt his first three words of draconic.

There exists a natural category of things, which are edible and not immune to fire, called food.
There exists a natural category of things, which compete for the food. He can hurt them but they can hurt him right back so he must be wary and cunning about it. They are called sibling.
There exists a natural category of things, which brings food. It is called mother.

When she next comes back he'll try a sentence.

"Mother Food".

That is not quite a sentence! You have to put Bring between them!

"Mother brings food".

This is indeed quite complicated.
He will try other combinations within his limited vocabulary.

"Food Sibling".

Sibling is not food, no.
You want me to give your sibling the food? Sure.

Words have betrayed him.

The fourth egg doesn't hatch at all, and eventually mother throws it out.