post-op confusion in 79 yr old

My father recently went through major surgery for bowel cancer, thankfully all is well, however, he has been paranoic, aggressive and extremely confused, he is now back on a general ward, been in icu for last 5 weeks, but is still very confused, staring into space and non communicative..(this is very out of character) Will this improve or is his mental state going to continue? I am worried he will not be able to return to his own home and to his own dependance, of which he was extremely proud. What if any, medical help will he recieve for this confusion?