The discolouration is a concern however it is hopefully something as simple as he doesn't have enough hard stuff to chew on to wear down the old portion of beak. Flakiness is normal, it has to do with how the beak grows (I'm not going to get in to that here, need diagrams to explain

). Offer him so natural (non toxic obviously) branches for him to chew on and see if this helps him wear his beak down. If not the next step would be to get him checked out if you can find a vet in your region who is knowledgeable about birds. May be worth ruling out beak and feather disease, it manifests so differently in each species...
Another thought I had was that the tip looked almost dead...this could be due to an injury such as a burn...has your bird inadvertantly bitten something hot and maybe damaged the beak lamellae??