severly beat with TBI

My great nephew was severly beaten 3 months ago.  Now he is recovering from a moderate to severe traumatic brain injury.  He has suddenly started eating like a  person who has been starved, eating 2 dinners w/ four pieces of chicken, 3 small containers of ice cream and tacos from taco bell.  He is 114 pounds and about 5'3.  He is small but has always been small with a normal appetite until recently.  He under went surgery to replace the section of bone taken out to remove a large blood clot on his brain. To this point he is a miracle!!!  But he has also been using a lot of profanity the nurses report.  My question (finally, i know) is this expected 'normal' behaviour for someone in his condition.