Social Security Questions? Ask a Social Security Expert
The answer depends on which type of benefit she is on. If she is on survival benefit from the deceased spouse, she should not lose it at age 79, an age larger than 60. If she is on spousal benefit from a divorced spouse, she will lose it if she gets remarried. But she may qualify under yours if you both marry more than one year. Some of the website links, citation references are enclosed below for your reference. Please verify with the SSA for the final authority on the matter.
Fiona Chen, MPA, Ph.D., CPA, ABV, CFF, CITP
According to the Social Security Administration's website, "If your widow or widower remarries after they reach age 60 (age 50 if disabled), the remarriage will not affect their eligibility for survivors benefits."