I don’t know of any study of Sam’s relationship with Henry, and as far as I 
know his autobiography gives the most insight. But your question got me 
thinking. Did Sam’s survivor-guilt after Henry’s death contribute to the 
splitting of his personality into the respectable SLC and the irreverent MT 
as he tried to bring Henry back to life?  In other words, was Henry (the 
model for Sid Sawyer in Tom Sawyer) also the model for “S. L. Clemens,” 
respectable gentleman and twin of Mark Twain?  Although I think there has 
already been too much pop psychoanalysis in Mark Twain criticism, it’s an 
interesting question, although probably, I suspect, an unanswerable one. 
Good luck, and I hope this helps. Life intervened in my case, too.