This suggest that Grendel intends to not meet much resistance.
He isn't considered honorable due to these acts
Explanation:
Snatching the men in their sleep and at night suggests that Grendel does not hope for much resistance from the men. Grendel comes when they're most vulnerable hoping to have an easy kill while the men would not be in the best position to fight back.
The alchemist says that the wind told him Santiago was coming and would need help. He instructs Santiago to sleep well, trade his camel for a horse, and remember that his treasure will be where his heart is.