Dr. Monzer Kahf, Scholar in Islamic Economics & Financial Expert, states the following: Hajj is an obligation but according to many scholars not immediately upon meeting the conditions of abilities.
On the other hand, the debts of one’s parents are not obligatory upon the person while saving the honour of the parents is obligatory. Therefore, if paying the parent’s debt relates to saving their honour I would suggest delaying Hajj and praying to Allah with good faith to make one able to go for Hajj next year.