Hi Lindsay, I'm not so sure that the Albert Gilbert in the 1850 Sacramento Census was your Albert. He's also listed with his family in 1850 in Division 20, Washington Co., Iowa. My copy of the Census has them indexed under the name of Gebhart. However, the wife and children's names match.
Also in the Iowa Census he's listed as a farmer and the Albert in Sacramento is listed as a shoe maker.
Have you looked for his death info in Washington Co., Iowa?
However, if you're sure the one in Sacramento is your Albert, finding a death record will be a challenge. Vital records weren't required in California until the early 1900's.
I'd contact a volunteer at Random Acts Genealogical Kindness. Go to raogk.org/, read guidelines, choose California and choose Sacramento Co. Then choose one volunteer.
I always found several Censuses where Ester lived after 1850 if you're interested. Successful Searching!