Because you both were co-signers that is why 2 1099C's were issued.
The 1099C only has to have the total amount reported once. So if it lists, for example, $100K forgiven, as long as the $100K shows up on one of the two returns. Your father could get a letter from the IRS two years from now, and he will need to show that you reported 100% of the 1099C. He would provide this information only if it is requested.
The tax law on forgiveness of debt on a home to be excluded from income was extended with the Feb 2018 budget bill that just passed, so it is possible that when you account for the 1099C it may not be taxable to you either.
Please click on the link below for more detail on this.
https://turbotax.intuit.com/tax-tips/home-ownership/how-to-avoid-taxes-on-canceled-mortgage-debt/L8j...
