SS, I also find the small incidentals make it appear him being the right man. But it's still not a confirmation in itself, which is what I'm now trying to establish to remove doubt. This is why I think trying to fill the gaps, which in themselves are an important part of the story, might be very helpful.
My Mother is appreciative and very interested, but she can't add much to what I tell her as its mostly all new to her. She was a very young child at the time. Neither can I overload her with verbal information as she forgets too easily, so I'm busy collating it into a written report she can read at leisure.
Yet occasionally some obscure snippet drops into conversation that she never mentioned before or couldn't connect to anything specifically.
This family history research is both fascinating and frustrating in equal measure.
Bob
I'm following this fascinating tale and amazing research as it has echoes of my own search for my mystery grandfather. I so agree with others that DNA would be useful if your mother can be persuaded. It's just some spit in a tube. But perhaps she is worried about what it might reveal, or concerned that she loses control of her privacy. DNA tests weren't a thing (or I didn't know about them, or they were too expensive - certainly not on my radar) when my mother wondered more frequently what happened to her own father, and although I did find out a lot about him eventually (thanks to RootsChatters) that then threw up a new mystery as to his father. My siblings/cousins have tested but her DNA would have been much more valuable for that research. But I do know my mother was surprised at how much personal information was out there about her family - just things like BMD, newspaper reports and so on. 'You can't keep anything a secret!'
Also I found incidental comments invaluable. There was an element of truth to all the oft-repeated anecdotes, plus I found just chatting generally about her family revealed more. Things like 'why did your parents give you your names' - it turned out that her name was in memory of another family member who I hadn't know existed. Other more general things about life or other family members, led to reminiscences that then triggered other windows into the past. Such as 'who was your favourite teacher', 'what was your favourite subject' - anything really that's nothing obviously to do with family history research but leads the conversation down memory lane where all sorts of snippets pop up.
As for occupations of fathers on birth/marriage certificates - in my family at least, their occupations were elevated if not totally fictitious.
Good luck with your search.