Don't know if this will help, but I had previously posted a biography of Johannes to the SnedekerCousins (YahooGroups) files. There was a fair amount of information concerning his family, etc. This was secured from a book that was prepared under the auspices of the Holland Society. At the very least, the information could possibly be used as a springboard for further inquiry, particularly as to the sources.
It does make mention of Johannes being imprisoned (along with his son Garrett!) at Sugar House while he was a patriot during the Revolution. It also states that "Johannes caught the smallpox and died September 28, 1779 (sic) in prison."