I am 66 and started collecting my benefits. My husband is 67 but worked for the post office for 40 years so is not entitled to benefits. Can he ever be eligible for spousal benefits?
Probably not. Assuming that your husband is receiving civil service retirement (CSRS) benefits based on his earnings that were exempt from Social Security taxes, any Social Security spousal benefits for which he would otherwise be eligible would likely be offset by 2/3rds of the gross amount of his CSRS pension. So, unless 50% of your primary insurance amount (PIA) is more than 2/3rds of the amount of your husband's CSRS pension, he almost certainly couldn't be paid any spousal benefits.
By the way, the offset described above is due to the Government Pension Offset (GPO) provision. For more information on GPO and it's exceptions, refer to the following Social Security publication: https://www.ssa.gov/pubs/EN-05-10007.pdf.