If Nael had just dropped the food off, or just handed it to Errol, he would have stalled until Nael left and then gotten rid of the food. This was because he didn't know what amount of food was suitable, he didn't feel hungry and he didn't feel full either, which meant that he would probably end up eating till he threw up again.
But now that Nael had offered to eat with him, he could just mimic the amount he ate just like he did at breakfast.
"I'll put a blanket out." He agreed without protest, getting up to do as he said.
Nael laid out the food afterward, he had gone for something simple, sandwiches and a slice of chocolate cake each for them. For breakfast, he had gotten an array of food again but stayed to keep an eye on Errol and he noted that Errol didn't start eating until he made a move, almost like he was mirroring his actions.