My mother's husband owed 70k+ EUR in taxes and at some point the judge proposed and he agreed to 2800 euros.

The trick is to not have a bank account in your name only, you have it joint with a child/spouse and they can't take your money. Nor they can take your house, if you only have one.

Eventually under those situations the judges try to take anything rather than nothing.

I'm not defending this situation, just saying it's widespread and the fact that every two governments come one that does a "condono", which is essentially "let's agree with tax evaders for some 50% of the tax they owe so they are happy and we see something" doesn't help.

Harsher punishment should be warranted, but you can't go to prison for tax evasion.