No the IRS will not know this ... simply correct the error as mentioned.
Now if you wanted to gift him something once you have filed the return and paid the taxes on it there is nothing preventing you from doing so. Be aware the annual gift limit is $16K per person per tax year. Going over that requires you to file a gift tax return. So you can gift some in 2022 and more in 2023.
Sounds like you were trying to split the tax burden between you ... so calculate your return without the sale and then add the sale ... note the difference in the bottom line to see how much the sale cost you in taxes. Then take that into consideration when making the gifts ... for instance if the sale costs you an extra $4000 in taxes on your return then when you gift to him reduce that amount by 1/2 the taxes you had to pay. Doing this makes you whole and he doesn't need to report it at all.
