Well, I'm researching a Cornelia Bradt born at about that time in that vicinity who had a son named Abraham (or Abram) Ferguson, born in Troy (i.e. close to Albany) around 1845. Her husband was John Ferguson. They lived in Rennslauer Co. by the 1855 Census (don't know why it was taken in mid-decade). That Census indicated Cornelia and her husband were born in Dutchess Co., but that Abram may have been born in Albany Co.
This seems like a likely connection, but the exact relationship would be hard to determine. Your Abraham Bradt is probably Cornelia's father or uncle.
On the other hand, it should be admitted that I don't actually know the Ferguson line very well, but it appears to have a number of Abrahams as well.