I have a client that filed single in 2018 and his wife filed HOH claiming the child, they should have filed MFJ. They separated in Oct. 2019 and should file MFS, she already filed HOH again and claimed the child. The right way to do it is for them to both file MFS especially since she does not qualify for HOH because they did not live apart for 6 months. But she has already filed as HOH and  since he filed Single last year should I just keep it that way Or open up a whole can of worms?