Wills, probate, letters of administration, powers of attorney
The simple answer is no he doesn't need any legal input, however that would be a very foolish position to take If he has anymore than one or two assets to bequeath things start to get complicated very fast As Joe has stated, spending a few hundred dollars to have a specialist solicitor draw up a will is both money well spent and offers peace of mind for all concerned.
He must also realise that circumstances are going to change, perhaps by not much, perhaps significantly in the time he still has left, be it days, months years or decades. Wills need to be kept current, relationships change, assets evolve and English can be a bugger when trying to be precise in declaring your intentions. See a solicitor.
And don't forget, if he makes a will, make sure someone knows he did and knows where it is stored.