With POA, I would like to find out whether it is worth it for my 96 year old mother to apply for her deceased husband's benefits?

lvmiami, I'd call SS to find out if they'll accept your POA at the local SS office or if you'll need to make another arrangement. Certainly worth investigating.

maybe you should also double check the reason shes not eligible for veterans assistance. https://www.benefits.va.gov/pension/spousepen.asp
its too bad if she was elig - and hasn't been receiving all these years. but there are requirements. but how you apply or check for her when you are out of state idk .

Did she ever remarry? If yes, that is a game changer. Everything is based around that 1 fact. If she did not remarry, she is eligible to receive half of his SS, that means if she gets 800.00 and he would have received 2,000.00 she will get 1,000.00. It is a and/or not both.

R u sure that dads SS is so much greater than moms that half of that would be better then all of her own. SS is based on 35 years of earned income, I would think based on your moms age that your dad was very young when he passed, meaning it is very likely hers is the greater of the two.

She needs to give SSA permission to speak with you or they have forms that she can give them that allow communication otherwise, not gonna happen, they will not disclose or discuss anything with out that permission.

Is there a phone number you can call ?

Mom was informed of dad's higher benefits a very long time after his death
SS applied retroactive payments for a short period of time