This "eat it or go hungry" attitude really pisses me off. It really does.
DS1 used to eat everything and anything until he was around 2. Then one by one, he dropped foods until there was bugger all left that he would actually eat.
Add into the mix his egg allergy and milk intolerence, you have the recipe for a really, really, limited diet.
He's 6years old now and only in the last few months have I figured out that he has had silent reflux and aerophagia since he was born. Aerophagia is the swallowing of air, and the more he chews, the more air he swallows. He burps the air back up and it brings stomach contents up too.
So, he avoids foods that need chewing - basically nothing harder than pasta. And the aerophagia makes him feel really full after eating a couple of mouthfuls of anything remotely chewy. That's because his stomach is full of air. He looks pregnant after chewing anything more chewy than bread.
He suffers aerophagia because he is tongue tied - a posterior tongue tie which you would never spot unless you were skilled in recognising tongue tie. He tells me now that many foods stick to his teeth (eg mashed potatoes) and he hates the feeling. He is not able to sweep his tongue round his mouth to remove these foods like somebody without a tongue tie.
He also avoids foods that get stuck in the little stringy bits on the floor of his mouth where his frenulum is like a web.
He tells me he would love to eat all the same foods as the rest of the family and he hates eating the same food over and over again. But it makes him physically ill to eat anything outside this comfort zone.
He will not be the only child with these problems. I guarantee you. Something like 10% of the population are tongue tied and a large number of them will have gone unnoticed.
So tell me please, how would "eat or go hungry" help???
And in answer to the OP, give the child whatever he will eat, or ask his mum to send something with him.