What counts as equity?

How is that supposed to work? That must then be taken out of your access for the duration of the financing, right? How else is the bank supposed to prevent me from blowing it all after signing?

For example, by investing in a fixed deposit, whole life insurance policy, or savings account and pledging it.

How is that supposed to work? But then it must be withdrawn from your access for the duration of the financing, right? How else is the bank supposed to prevent me from blowing it after signing?

Pledging or assignment.

That is clear. But then I can no longer use it for the original purpose either.

When enough has been paid off... Of course.

Can you increase the equity ratio through the house and property of the parents? In other words, then take this as a mortgage. Or does that make little sense because the liability risk for them would then be too high, although I will probably inherit it!?

Yes, it can be done with the already recognized risk for the parents as well.

You can also become insolvent before the parents pass away.