If you and your spouse were not married to each other in all years (2017) involved in figuring NOL carrybacks and carryovers, only the spouse who had the loss can take the NOL deduction. If you file a joint return, the NOL deduction is limited to the income of that spouse.
the 2018 loss from H's S-Corp is not a NOL but part of his current year net income. so he can use $10K of the 2017 carryover. I am assuming he has basis in the S-corp to take the $20K loss.
