Bought a house but absolutely no idea about the subject

When purchasing, you have a special right of termination with all insurances. So if you ever want to "clean up," you can have everything transferred to your name.

I would recommend you put everything in your name and then share it with him with a clear settlement.

Maybe you should assign him a fixed apartment. So possibly divide the apartments and assign one to him.

Strange case. If the house has a value of 250k, then the right of residence must be deducted from that - and it adds up! A person can grow old..... So you would have to base it on the average age reached. Then a capitalized rent over all those years. That would certainly result in a value well below 200k. This calculated value would have to be applied. That your mother then has her divorce-related dispute with your father should be none of your business: Therefore, it was already a huge mistake to pay your mother 115k. Sorry: You really didn't think that through much. And as always with real estate: NEVER let yourself be put under pressure. One option would have been, for example, to fix a gratuitous right of residence for 1 or 2 years (if at all!) and then set a rent (including a defined index): As it is now, you are the one screwed over - won't help you much, I know. What did the notary say? He is obliged to make you aware of the consequences, isn't he?

That your mother and your father have their divorce-related dispute should not concern you: Therefore, it was already a huge mistake to pay your mother 115k

Why: The parents were presumably 50:50 owners.

The OP purchased the house for a purchase price of 115K + the father's right of residence registered in the land register.

That the 115K€ then went only to the mother can be of no concern to him, that is really a divorce matter between the parents.

The right of residence thus has a value of 135K€, depending on the father's age this results in a cold rent of 350 - 600€ per month for the rest of his life. Yes, the father lives relatively cheaply, but this is not unusual in intra-family rentals. Because ultimately, the "saved" rent accrues to the inheritance or is saved for later care and thus possibly relieves the son.

But now it doesn't matter, he wants to spend his 30K renovation loan and doesn't know where to start. Roof, windows, heating, sanitary, electrical, floors... ... either only the bare minimum everywhere or one or two things completely and properly. Consult a building surveyor who will most likely say where the shoe pinches. Because a construction company will first propose what makes the most money, but not necessarily what is maintenance-wise necessary or energetically sensible, etc.

About the contracts: Call providers, insurers, etc., describe the case of the house purchase and that the seller does not hand over any documents. They will then send everything again (possibly for a fee).

Before you invest money in a renovation, I would honestly make sure that the right of residence in the land register is limited to individual rooms - if the father currently has a right of residence "in the whole house," you cannot force him to move to the first floor! And then the father should actually move. Only then would I invest any money in the house once the living arrangements are clarified.

I would spend the money on creating two spatially separate living units!
This is not ill will toward the father, but you want to get married and start your own family, so in my opinion clear boundaries need to be set. I would set those boundaries before the fiancée moves in or money is invested.

And whatever you do: keep your girlfriend financially uninvolved. Agree on a lease with her if you want, but she should definitely not sign any further loans or similar.

Hello, your father will get in touch when the payment is deducted from his account.

Would also try to create 2 separate residential units. Whether 30 grand is enough for that is, of course, questionable.

Nice parents, by the way. When you consider that you would probably have inherited the whole house later anyway... :(