Well if he stops eating death can occur but i'm sure they'd put him on a drip to feed him so calm down.

This sounds abit like some sort of allergy (or is he being given his food too hot?- this can happen with new mums who just don't cool the food down to baby level as opposed to toddler or adult!!)??

Has he been tested for allergies? Have his parents (& this is an a- grade pain - put him on just one food type (with no additives/preservatives) for 2 weeks then slowly added (1 at a time for several days before adding the next) other foods - this is a really hard but veru effective ay to find out if he is allergic to anything & if so what. You add the foods with additives & preservatives last & the added bonus of this is that it can show if his behaviour is adversely affected by anything too.

Several years ago I saw a story about a couple of kids who were lacking in something & so they were eating anything & everything wooden (fences/toys/beds/cupboards anything!!). Maybe he's lacking some vitamin or mineral or his body just doesn't process it properly & the red tongue is the outward sign??