I saw that dodgy performance as well and thought that perhaps like most people his voice had dropped with time. The presenters asked, or expected, him to sing some of American Pie, and he attempted it in the key he recorded it in about 48 years ago, rather than dropping it by a tone or so. Since it was in G major, I suppose it would have been difficult to play in F and retain the same open guitar sound (eg. B flat, F, C etc). It was also the Breakfast Show, and who can sing well that early in the day? Your own vocal range sounds about the same as most of us, ie less than two octaves and being able to render songs about a tone higher and lower than your ideal key.