I have no specific information on August Sy, but I have been researching the origin of the names Sy/Sye, etc.
The surnames Sy/Sye/Sieh, Zeek and Sickama, are shown in two texts on Surnames to be of Frisian origin, a medieval surname taken from the occupation of "seal maker". The earliest reference to Sye that I found would have been around 1067 in Hamburg. Sy would have existed at the same time. Frisia as a nation had signed treaties with Rome around 2AD, and was situated south of Denmark. Most of the names in that grouping are still found in the Schleswig-Holstein area of Germany. Only a few are found in the Netherlands where Frisian is still an official language, but there were mass emmigrations from there when Spain ruled the area.
The only other source for the names that I have found are changes in spellings from the Walloon and Hugenout groups, where a surname "Six" existed. On arriving in England they changed it to the phoenetic equivalent Sy, and then some added an "e" to that. There are detailed records of those families in England.
If you go to http//www.familysearch
the LDS site and make inquiry on Sy in Germany with the "any spelling" option, you will see a number of names there. If you can find the site to check for white page listing in Germany for Sy, you will see some listings there as well. I seem to recall around 130.
There are many Sye names in the US, most of them shortened from other spellings or unrelated. I have not seen that with the Sy name.
Frisian and German groups will tell you that surnames were only recently used there, and that is true for the most part. I have traced Sye back to before 1500 in England. Based on their given names, and marriages to Germanic families, as well as being found in a location where refugees from Amsterdam settled, I tend to believe they are descended from those Frisian folk. That and the fact that all the names except Sickama are still found in what was Frisia, leads me to believe that they passed on the Surname from the time it originated.
If I run across anything specifically on August, I will pass that along.
Richard Sye firstname.lastname@example.org