you can't stop her from claiming your son. if she has e-filed and you try e-filing your return claiming your son it will be rejected. (the first to file gets to e-file. the second to file must mail in their return.
eventually, the IRS will send each of you a notice asking you to amend. if neither amends, then the IRS sends a second notice asking for proof you're entitled to claim the exemption. the one with the best proof gets the exemption the other gets a bill.
here are the rules for claiming a child
1) be the taxpayer's child, stepchild, eligible foster child or descendant of any of them such as a grandchild or brother, sister half-brother, half-sister, stepbrother, stepsister or descendant of any of them such as a niece or nephew, legally adopted child or place with the taxpayer for legal adoption
2) be any of the following a) under age 19 at the end of the year b) a full-time student and under age 24 at end of the year c) or any age if totally and permanently disabled
3) child must have the same principal abode as the taxpayer for more than ½ the tax year.
4) the child hasn't provided over ½ his/her support
5) No joint return with the exception for a joint return filed only to claim a refund of tax withheld when neither spouse is required to file and no tax liability would exist for either spouse if separate returns were filed
6) Not be a qualifying child of another taxpayer with a higher priority under the tie-breaker rules
if these tests are met he's your qualifying child. your mother can't claim your son because he's your qualifying child. I won't go into whether it was proper for your mother to claim that son in prior years. however, if she doesn't qualify and is caught, she could face substantial penalties. she would lose any child credits claimed and her status would probably go from head of household to single resulting in higher taxes.
Well are situation in prior years was a lot different then it is now and i work my butt of and provide for my kids and i feel i should have every right to claim them on my taxes but my mother however feels obligated to do whatever she wants and insists she has seniority of me because we all live together and share the rent and utility's equally, but when it comes to my kids, I provide their food, clothes, transportation and money to my kids all on my own and I feel i should be the one claiming them!
You just have to let the state dish it out. Being as how you have supported the children, they will just prove that your son was in your care. Such as school documents, receipts of any kind showing if you bought his clothe, food, etc. if you have any documents from doctors, I would gather all of that showing if you took him to the doctor at all. The best thing that you could do would be to get a paper from the school showing where your son resides. Get all of that documentation together and have it ready, just to have it on hand for when they need proof of where the child resided for the most of the year. Your mother, would have to prove that she had him for over 6 months of the year, provided food and shelter and or transportation to and from schooling if trying to claim him and if they give her money, she will have to pay it back if you prove that you had him.
And/or with you living in the same household, they may split the amount for the qualifying child. So you get half and she gets half. It’s basically up to the state after they take everything into account.