My husband died in 2012. I am currently 62 years old. I was told by SS that at my full retirement age (66 1/2) that I could take 100% of my deceased husband’s SS and still work full-time. I intend to work until I’m 70 and invest his SS. My question is if I do that can I, at 70, switch to collecting my SS (which will be larger than his), thereby stop collecting his or will I have to continue taking his and forfeit mine?
I'm sorry for your loss.
The answer to your question is a definite yes. In fact, depending on how much you're earning you may even be able to start drawing benefits before your full retirement age (FRA). If you were born in 1957, your FRA for widow's benefits would be age 66 & 2 months even though your FRA for retirement benefits on your own Social Security record would be 66 & 6 months.
However, your FRA for purposes of the Social Security earnings test (https://www.ssa.gov/planners/retire/whileworking.html) would be 66 & 6 months regardless of which type of benefit you claim. That means that even though your widow's rate would be unreduced if you claim benefits at age 66 & 2 months, your benefits could still be subject to withholding due to the earnings test until you reach age 66 & 6 months. Whether or not you could be paid benefits before age 66 & 6 months depends on your benefit rate and the amount of your earnings.
Assuming that your age 70 Social Security retirement rate would be higher than your unreduced widow's rate, your best filing strategy would almost certainly be to claim widow's benefits as soon as your earnings would allow you to be paid at least some benefits, then switch to your own benefits at age 70. Our software (https://maximizemysocialsecurity.com/purchase) could help you sort all of this out so that you can choose the best possible strategy for maximizing your benefits.