Who can contest a Will?

Please accept my condolences on the loss of your ex and please provide your son with my condolences on the loss of his father.   As for your question, your ex was legally entitled to leave assets to whomever he wished (I'm assuming he was a Georgia resident, but this statement is generally true anywhere in the US), as long as his Will was valid. If you believe that there are strong grounds to believe that the Will was not valid for some reason, then your son, as one of the heirs (along with your ex's current spouse and any other children who he may have had via birth or legal adoption) does have the right to try to challenge the Will. However, whether you can bring that challenge on his behalf is a somewhat different question. To do so legally, you would need to have the legal power to represent your son. You may have that power if he is under 18, or if he is legally incapacitated and you have been legally appointed as his guardian or conservator, or if he has signed a power of attorney that gives you that legal authority. But without knowing more about the actual facts of your son's situation, no one will be able to advise you as to whether or not you can sue on his behalf. You will need to get a consultation with a fiduciary litigation attorney in order to find out what options your son may have to make a Will challenge and what ability you might have to help with that challenge.   On a related note, if your son is under 18, then he has the right under Georgia law to file a Petition for Year's Support and ask for assets from his father's probate estate no matter what the Will says. This may give hiim the ability to receive more than he would otherwises. However, this is again something for which he will need to seek the help of a fiduciary litigation attorney. And timiing may be critical if he is near 18, because the Petitioin MUST be filed before his 18th birthday.   So, get a consultation for your son with a fiduciary litigation attorney. Soon. The attorney can help your son consider his options and the likely costs and risks of bringing a challenge or filing a Year's Support claim. The attorney can also help you determine what steps, if any, you can take on your son's behalf. Best wishes to you.