Yeah, the more I think about it, the more I may tell them to go elsewhere - she only made 12k and got a huge Earned Income Credit - the BF made 70k, so yeah - they did their respective 2020 returns incorrectly.

They are not going to understand they did things wrong - I may ask if they lived apart in 2020....she with the child and he somewhere else, but there is a reason we fill out those due diligence checklists...

btw, I saw someone on one of these forums talk about "choosing" who could claim HOH without mentioning the tie breaker rules - I thought to myself "wut? Did something change" and went down that rabbit hole looking to see what I missed.