My 'rule' with food here is I offer up a good meal. I don't pressure, encourage, push, bribe or force a child to eat anything. They are in control of what they put in their mouth choosing FROM WHAT I OFFER. I try to include one 'safe' item with each meal whether it be a simple veggie or a fruit since my meals tend to be more adult oriented. If the rest of my group (all same age) can handle cabbage rolls and stir-fry's then so can the picky child that refuses.
I don't stress or worry about their intake. I have a 16month old that eats nothing. She is catered to at home and eats a select few (rather unhealthy BUT ORGANIC) items. What ever. I do an extra mini snack before afternoon nap as my group is all 13-17months old and all still nap twice a day. We have lunch at 11am but nap at 1. I now give a half cup of milk and a cracker of some sort right before 1pm so they aren't starving and sleep 2hrs. I find 4.5 hrs between lunch and snack too long for these little ones.
I would honestly tell you to stop caring. The family needs to put the work in to deal with it...possibly with professionals. The food things could very well be related to the not talking. There may be a real issue here not just a stubborn eat (though having been fed purees so long makes it seems like a learn behavior).
Keep offering let the child take charge in their intake just put it in front and clean it up at the end. It quickly becomes a power struggle if you start trying to make them eat...even the games of encouraging can become a power struggle. Ignore if they whine, chat with them if they are calm...just don't mention their food.