When I graduated college 18 years ago I was only offered 10yr repayment and unsubsidized loans were 6.8%, which means a $70,000 loan at 6.8% interest repaid at $500/month would take 23yr 4 months and would have a $1494.34 balance after 23 years of monthly payments. 
o have 60,000 remaining balance after 23 years of monthly payments on a 70,000 with a $500/month payment means a 45year note at 8.375% interest.  

Some either deferrred payments or there is far more to the story that what is told.