Student loans are usually written off and Forgiven once the Student reaches age 60 or when 25 years have passed since the student loan was taken out.
However for a student loan to be forgiven at age 60 or when 25 years have passed you must be enrolled in a payment plan and be making payments on those student loans during those 25 years for the student loan to be forgiven and written off.
Student loans don't just go away after 25 years or when you reach age 60 unless you have been making payments on them during that time.