Sadly, the ancestry of this particular Alexander WEATHERWAX continues to be part of of one of our great enduring family mysteries. Very early on in my research, a family member and I pondered at length over the ancestry of his West Glenville, Schenectady Co., NY-born Weatherwax great-grandfather. We wound up going around and around in circles...getting absolutely nowhere, of course! Several years later, a Michigan descendant of your Alexander also contacted me. When we were in NY in 1987, my husband had transcribed the marriage record for Alexander and Isabell, so we were at least able to share that with her.
I have written data on this branch of the family deeply buried somewhere in a filing cabinet. I have never been able to add it to my computerized database because there is simply no existing connection to the larger family.
I have a STRONG suspicion that this Alexander Weatherwax was a grandson of my 4th great-grandparents, Alexander and Jannetje (VAN BREMEN) Weatherwax, but so far no such link has been found...much less proven. I am a descendant of Andrew Weatherwax (1768-1847), the eldest known child of Alexander and Jannetje. Fortunately, my particular branch kept pretty accurate family bible records. The other two known sons of Alexander and Jannetje Weatherwax were Thomas A.(1780-?) and Alexander A. (1782-1852). The couple also had a daughter, Jane (1770-1854), who married Banjamin ELIOT.
The Alexander Weatherwax who married Isabell Milroy was probably a son of either Alexander or Thomas. One of these days, one of us will hopefully stumble across some crucial data for the families of these two sons and rescue them from the depths of my file cabinet (otherwise known as genealogical oblivion.) Until that happens, we are all likely to remain caught between a rock and a hard place in regard to the ancestry not only of this Alexander Weatherwax, but of any other descendants of Alexander A. and Thomas A. Weatherwax.
Sorry...I wish I had something more hopeful to report. Military records would probably have been very helpful in this case, but this particular Alexander (born 1803) was too young to have served in the War of 1812 and too old to have served in the Civil War.