He was quite eccentric and by all accounts a very good artist.
I have researching him along with my family history for years. He is just one branch that unfortunately has been very difficult to unravel. So much public info due to his work but so little discussed within the family since my Grandfather and Aunt were so young when they last saw him.
As for the Smithsonian, goto their website and there is contact info for the art staff. Good
Luck!!