Yes, you should both report half if filing separately. If he has already filed and claimed the full repayment, you will need to paper file or you can try to add $1 of repayment to your return and see if that will allow you to e-file.
Per Form 5405 instructions:
If you and your spouse claimed the credit on a joint return, each spouse is treated as having been allowed half of the credit for purposes of repaying the credit. Each of you must file a separate Form 5405 to notify the IRS that you disposed of the home or ceased to use it as your main home and figure the amount of the repayment.