Hi Pat, I'd like to help, but I'm a little confused.
As I understand it, your husband's grandfather, William A Bresie, was born December 18, 1873 of unknown parents. You suspect he was born in Michigan, but are not sure??
It appears you also know he migrated from Stittsville, Michigan to Texas in 1889, but are not sure which county he migrated to, or whether he went alone or with his parents. If your assumptions are correct, William A would have been about 16 years old at that time, and most likely single.
You've also found several birth records from the West Copake Reformed Church, NY for William A Bresie. I'd be interested in knowing what those records were.
The only William I can find in the 1880 census who was born in 1873 was born in Sharon, Litchfield, Connecticut, William Brazee, parents Charles Brazee and Naomi. No William of that birth year appeared in the Michigan census for 1880.
I have the following suggestions for you in pursuing your William A:
First, don't get hung up on spelling. I've found that surnames of Brazee, Brazie, Brasie, Bresee, Bresie, Bresse, and several others are most frequently related. On the other side, surnames of Bracy, Bracie, Brees, Breesee, and Bries are usually not related to the Bresie line except for the occasional accident of spelling.
Next, if you can determine which county in Texas the family migrated to, and have access, you might check the 1900 census to see if you can find him there. He would probably be married. If he migrated with his parents, they might be somewhere close.
A final thought. Probably all members of this line originated from Christopher Brussi/Brazee/Bressie and Christina Claesgen (aka Styntje Class) of the Albany, NY area in the late 1600's. Second and third generation Brazies were mostly in the Columbia County, NY, Berkshire County, Mass, and Litchfield County, CT areas. There were a few in other places, but the largest concentration was there,
Some early Brazees migrated to Michigan. The largest migration occurred probably just after the Civil War. Some stayed, some moved on, some came back.
I hope this helps. I'm chasing Williams too (my GG Grandfather was William Brasie, Jr), so let me know how you are doing.