Eunice probably died between 1825-1830 in Rush.

The attached family list image is a reproduction from, "Pt. 1-3. Descendants of Daniel, James and Joshua Brainerd, Sons of Daniel and Hannah (Spencer) Brainerd".

It is a ROUGH outline of known, or PRESUMED information about the family. Most or ALL of the located children were NOT born in Rush, but moved there as young children, and that's where they came of age.

Samuel & Eunice were in Stephentown, Rensselaer, NY in 1800. They were in Nassau, Rensselaer, NY in 1810, both very close to Philander's birthplace. They finally made it to Rush, Ontario, NY by 1820 (Rush would merge into Monroe County in 1821). All of the children up until Philander would've been born in Rensselaer County, and all known were born by 1814. The following few from the list will be worked on to see if they can be verified:

Susan b. 1800 in Rensselaer County (died before 1810)
Samuel b. Sep 1802 in Rensselaer County
Timothy b. 3 Jun 1804 in Rensselaer County
Paulina b. _____ in NY (b. 1812-1820)

I also found a Norman in Prestonville Cemetery, where Brainerd & Philander are buried, and I have presumed him to be their brother.

UPDATE: After retrieving Philander's obituary, it confirms that Norman WAS his brother, and that he DID have a brother named Austin, who I removed from the shortlist above. Crazily enough, Austin was the first husband of Philander's wife, Betsey. He only lived about eight months after marriage. That was an exciting mystery to recently uncover, as Philander & Betsey are my 3rd great grandparents!

Daughter Sophia's sources say she was born in Connecticut. My guess is the family may have traveled home for a visit, and she was born at that time. Connecticut was very close to this eastern NY area.