The planner does not perform any calculations according to DIN 276

I have to admit, bit by bit I somehow have a completely different picture in mind than the OP is trying to describe. Now suddenly 80 k€ turns into 67 k€. How much of the rest is then correct? Was there really only one offer per trade everywhere? Is it really 12 k€ more for the scaffolding or is that the total sum? Is there really no cost breakdown? There also seems to have been some incident, that the architect no longer dares to meet her clients without protection.

I am sorry – due to the emotions that arose / arose I got confused with some numbers. Regarding one offer per trade – I can say that I have not even come across an offer from several companies. The companies came from all over NRW – of course they were always supposed to be the best,…

There was never an incident – except for a loud warning from me that she almost drove my father to ruin and that people like her or me would have long since gone bankrupt with a planner like that

Ex

You can easily find that out with a call to the Chamber of Architects, right?!

I wonder about that too.
Ultimately, the renovation is completed, isn’t it? If she now sends invoices for services she did not perform, you can hire a lawyer to enforce "his right," namely your father’s.
Meaning: your father’s duty. Your father’s mandate.
It seems to me you now want to retrospectively fill your father’s account with "rights," although one probably should have taken action in time back then?

A lot has to be written off later as tuition fees – it doesn’t matter whether you naively paid invoices or because it got out of hand.

I don’t want to fill an account – I just want to limit his damage.
She has responded neither to his nor my inquiries verbally or in writing / as I said, her only statement regarding DIN 276 was initially / that she did not have to provide it, then that she was not even aware of it!

Then withhold the money and justify it with the incomplete service within the period for objection. You write "initially" - what else do you want?

By the way, it is 67,000 plus 25 percent due to the monument and additional effort - that is correct.

I just want to limit his damage

Honestly: There are some questions from you where one could get the answers sooner or later in one day. Then it's a matter of consulting a lawyer for civil law, definitely not a new idea. And then, I want to point out, the house construction/renovation after your initial post lasted 4! In words, four years, and now here you come. Where were you during all those four years when the damage occurred? Wouldn't it have been time back then to assess the situation? You of course don't have to tell me or a forum where you were. That’s none of our business. But maybe you should consider what you’re trying after several years. Especially since you spend several days here, as if you could reverse time and the situation, while in real life life apparently goes on.

By the way, it is 67,000 plus 25 percent due to the monument and additional effort

Which 25% because of the monument and additional effort? - that is what the difficulty levels in the HOAI table are for!

What is wrong with you? I thought a forum like this was meant for asking questions. I just see the "powerlessness" that leaves one speechless. How many inquiries have been made - whether orally or in writing / everything has been ignored. I originally just wanted to know if the architect's claim is correct that she does not have to produce any calculations according to DIN 275 - and also no cost determination - which would now be very interesting after completion. That’s what we paid for, isn’t it?! The final invoice is now available - and once again all inquiries are being ignored and the deadlines are running out. The reason I am only getting involved now is simply because I have only now become aware of my father’s helplessness (he has greatly deteriorated in the last two years), since he has now opened up and honestly admitted that he can no longer defend himself!