Dependent fraudulently claimed by now deceased grandfather

[rb8383]

My father passed away 18 months ago ,and while going thru his things I found his tax returns for the last 6 or 7 years and on all of them he had claimed my son as a dependent when I have/had always had full and sole custody of him and he lived with me. I knew someone kept beating me to claim him year after year and I always assumed it was my son's father and I didn't want to bring him any trouble so I just let it happen. Now I have discovered it was actually my own father! With him being passed on is there anything i can do to get those child credits /money back? It's quite a lot when you add it up. 

[ee-ea]

Have the executor of his estate file amended returns.   Info on amending is here:    https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...

[Mike9241]

even if the executor files amended returns, you may be too late to claim refunds for any year prior to 2019

you should have filed by mail in every year you were rejected. then the IRS would have asked for proof from each of you. assuming you were the one legally entitled to claim the dependents you would have gotten the money and grandpa would have gotten a bill. you may have a claim against your gandpa's estate but for that you'll need to see a lawyer.   meanwhile, if you didn't claim the children you need to amend 2019 through 2021 to claim them.