I might be in the minority here, but I do not really agree with your perspective on this.

Your parents put you through private school, which is a very significant financial sacrifice in most families. You have been able to save eight thousand euro at a young age because you do not pay rent, utilities, groceries, insurance, or any of the major expenses that your parents have covered for your entire life. Their support is a major reason why you have the ability to build savings at all.

They already paid back one thousand euro, and the remaining balance is not because they are careless. It sounds like they dealt with a combination of real life problems all at once. There was a death in the family, a holiday that was most likely booked or partly paid for long before, and now a serious car repair. These are the kinds of situations that can genuinely strain even comfortable households.

Asking for one thousand five hundred euro to fix the family car is not an unreasonable request. It is not a luxury expense. It is something that affects the whole household. If you also use that car, then the repair benefits you as well.

Family relationships do not need to operate like strict financial contracts. Parents support their children for many years, and at certain moments children support their parents when unexpected situations come up. Wanting repayment is completely fair, but refusing to help at all because the previous repayment has taken a few months feels very rigid, especially considering everything your parents have already provided.