Actually no. gM, even without the forged long ending, is fiction. It is not possible to tease out any "historical core".
About the only thing HJ proponents have to hang their hat on is "James, the Lord's brother". And HJ proponents must admit the controversy surrounding that phrase.
In the end, we cannot know if there was an HJ. I am beginning to have serious doubts an HJ existed but will state we can't know either way.
I agree;- those few words in Paul's letter are probably the strongest evidence that any HJ case has.
People might decide to believe in a HJ for reasons that are not actually derived from the written evidence (though there is no other "evidence" except for what was written). But that's really a matter of placing one's faith in the religious faith and un-evidenced beliefs of 1st century religious fanatics, all of whom were certain that Jesus was a multiply miraculous supernatural figure.
But here are some of the problems with that remark in Paul's letter
"save James, the lords brother" -
1. It is by no means clear that Paul meant anything other than a "brother" in belief. Because Paul very often used the terms "brother", "brothers", brethren", sister", "sisters", but almost always only to mean brothers and sister in religious faith.
2. Those particular 5 words " ... save James, the Lords brother", were mentioned once in that one half-sentence, and never again repeated anywhere in any of the letters. Never again was there any mention of anyone being the actual brother of Jesus, or even of anyone ever having met Jesus at all.
3. That same James was supposed to have written his own gospel. But in that gospel he makes no claim even to have ever met Jesus, let alone been his actual "brother".
4. It is far from clear that those few words were ever originally written by "Paul". The form of that sentence suggests the words may be an addition by a later copyist. To explain that -
- that sentence would have been complete anyway without any mention of the name James. I.e., the sentence says "Other apostles saw I none" ... but then as if by afterthought the writer adds "save James" ... and then as if in another afterthought for the benefit of anyone who did not know who "James" was, he adds "the lords brother".
E.g. as if writing it like this -
"Other apostles saw I none ... oh, except that is for James (I forgot about him) ... he is the lords brother by the way (in case you did not know)".
That's exactly the sort of way in which copyist alterations were often added, i.e. as extra explanatory words.
5. Copyist alterations of that sort were apparently (according to bible scholars), common. So it would hardly be a surprise to find a clarification like that was something that had been added over the centuries.
6. Out of 13 letters once all thought to have been written by Paul himself, 6 or more are now thought to have been written by someone else entirely. That clearly raises doubts as to who actually wrote any of the letters under the name "Paul".
Just as a further comment on 2 above, where Paul is supposed to have met the very brother of Jesus - only a few years before that meeting with James, a vision of Jesus had completely changed Paul's life, so that from that moment on, Paul did nothing else except preach Jesus to everyone and anyone all day long every day. This is a Jesus who Paul himself had never known, but who has now become the most important thing in his life and his only reason for living. And then, he meets "James, the lords brother", and apparently he does not ask James a single thing about Jesus. And James apparently tells Paul nothing about Jesus. In fact none of them discuss Jesus at all!
That might not be surprising if Paul only regarded James as a "brother" in the faith. But it would be unbelievably amazing if Paul thought he was meeting the very brother of the Lord and Son of God himself.
All that said - of course it’s possible that Paul did meet someone (James) who claimed to be the very brother of Jesus. But in that case it’s very strange that neither Paul nor James nor anyone else ever described knowing or meeting Jesus at all. E.g. virtually no human details of Jesus are given anywhere in any of the 13 Pauline letters. Instead, practically everything that Paul ever says about Jesus is very obviously theological. Even the 2 or 3 times when Paul does appear to mention some human act by Jesus, iirc he always adds that it is known “according to scripture”.
We might also add that even after all of that, the extant copyist versions of Paul’s letters have apparently all been found, not anywhere near Judea where these events were supposed to have taken place, but from people apparently writing in Egypt!
