Who says, "Let him eat honey" in Beowulf.
In the new translated account of Beowulf and Wiglaf's fight with the Firedrake (dragon), Beowulf's trick is to get the Firedrake to swallow the Queen Bee so the other bees will follow and sting the Firedrake's fire-breathing throught. Some translations end with Beowulf yelling, "No, Let him eat honey!"
Also, the name Beowulf is itself a KENNING, meaning “bee-hunter.” The "Beo" means "bees," like honey bees (bears' favorite edible). So, "let him eat honey" is a kind of war cry for someone whose name is Bee-hunter.
Here's the Robert Nye (1968) adaptation:
The Firedrake saw them coming. Its gold eyes bulged with fright. It tried to shut its mouth, but the stake between its jaws prevented this.
The bees poured down the monster's throat like a stream of honey, in pursuit of their queen. But when they reached the Firedrake's stomach their effect was like no honey in the world.
They began to sting!
Hundreds of bees, stinging it from the inside!
The Firedrake roared with pain and fury.
It tried to spit out bees. But there were too many.
It tried to spew up fire. But its own insides were burning.
Little Wiglaf danced with glee.
But Beowulf had collapsed in the entrance to the treasure-chamber. His armor came undone. It was all too big and heavy for him.
Some men said, long afterward, that Beowulf was killed by the burning breath of the Firedrake. But, in truth, the monster managed only the merest tiny little cough of smoke before turning over on its side and giving up the ghost. Beowulf's bees had stung it to death.
The Beowulf novel that you are addressing is actually a children's story version called Beowulf: A New Telling, and it is somewhat different than the epic poem. The story is different in that Beowulf is a smal not very big guy but he has a huge chest with muscles who goes to help King Hrothgar’s kingdom. (This is the same in both).
In the story, like the epic, Beowulf fights the monster Grendel and wins. He tears his arm off and then chases him to his lair where he beheads him.
In the story a slave runs away from a kingdom after being repeatedly beaten. Beowulf shows the man compassion and kindness by giving him honey to eat. However, his men took that as a sign of warfare.