I think you have to consider that he's using an assumed name ... no sign of him prior to his 1951 marriage…
I don't like to ask…I think the same as you though in that Denver changed his name.
I believe all family “facts” and family stories have a ring of truth to them (if they aren’t actually true). However, for the family not to be found, so far, in
any documents makes me believe that possibly details were either unintentionally or purposely muddled.
To state that the family lived in Brooks seems quite possible; being so specific about his birthplace, when he lived so far away, has a ring of truth. However, was his father truly born in England and was he really a trapper (I think that was mentioned early on). Quebec (Canada) has been brought up as possibilities I believe; I’ve also run across Talbots from Quebec but have discounted them because of his supposed birthplace.
…Denver told his son, my friend, where was born etc. Brooks Alberta, to an English but possible Scottish man and a Blackfoot indian woman.
If Denver’s details cannot be found, would you feel comfortable asking your friend if his father had an “unusual” accent or used unusual words? Even if he lived in Wales for a long time, he might have still retained his accent, or regional phrases/words, from his early years. Could any words indicate an English or Scottish upbringing? I’ve lived in California a long time but periodically people will question my speech (using a word like serviette tends to confuse people).