Hi & Welcome,Firstly do you have any background on the bird ? how was he treated, Is he bonded to anyone,Older birds can certainly be successful, but there is lot of potential for problems. An older bird that is not tame will be very difficult to tame & require a great amount of time spent working with him.A tame older parrot may be very bonded to its previous owner and many not be as tame with a new owner,at the very least it may take time and patience to get such a bird to fully trust and start to bond with you,I would say be prepared to accept the bird for what he is, if he extends his vocabulary then treat it as a bonus.