Single-family house from 1977 unheated for years. Risk?

You urgently need to find out what the basement is made of ... Brick? Concrete? And then I would use a moisture meter where the plaster is flaking off and on all the walls in general ... You can buy or borrow one, or an expert will have one with them as well. I wonder how my predecessor wants to judge that based on pictures.

To shed some light on the situation: We decided against the house and have closed the door in that regard. However, another one has opened elsewhere, with one foot already in and the second one lifting off.

Thank you for all the feedback!