I have a situation where a separated spouse (divorce pending) filed her 2021 tax return using the MFS filing status, and received her refund. I am now working on the husband's tax return. I was provided a copy of her tax return, and have determined that if the couple could agree to file jointly, they would net about $5,000 in additional refund. Since he has not filed yet, I believe to change from MFS to MFJ, her return would have to be amended to accomplish this by adding hubby's income and deductions. They could enter into some sort of binding agreement as to how to split the refund, but he would be entitled to the bulk of it. I presume that if her return is being amended, she would be the primary and the refund check would be mailed to her. Not sure if he is going to be comfortable with that. Can a refund check be mailed c/o a third party custodian to be sure it gets distributed per the agreement? Have any of you faced a similar situation, and how did you handle it? Thanks.