Simple answer: No.
The event of paying off a student loan is not deductible by anyone.
Only the interest paid on a student loan is deductible. You cannot deduct that interest, even though you paid it, since you were not legally obligated to do so. There might be one exception: if your spouse co-signed the loan with his/her son and you file a joint a return with your spouse.
Your stepson may deduct the interest you paid, under the theory that you paying it was a gift to him and it really was him paying it.
If educational expenses were paid with loan money, in 2020, those expenses qualify for the student (or whomever claims him as a dependent) to claim an education credit
