Transfer of ownership of a house
My mother is 68 years old and widowed. She has given birth to two children. My younger brother tragically passed away nine years ago. The different forms of grief and coping have led my mother and me to drift apart. But that's just a side note for better understanding.
For about ten years now, she has had a steady partner who is the same age as me - I am 40 - but since 2001, their relationship has been more of a practical partnership rather than a romantic one. Despite having undergone several heart surgeries, my mother is still independent. Her partner, who is a nurse by profession, lovingly takes care of her and has been living in her house for about a year now.
Due to the unique circumstances, my mother transferred ownership of the house to him, which she claimed was not worth much anymore. She estimated the market value to be around €65,000 or €35,000. She then asked me if I agreed to this arrangement. I agreed, as over the years I have visited my mother regularly, but due to our differences, I never stayed long with her, let alone cared for her. As compensation, she set up a fixed-term deposit account of €10,000 for my son, her grandson, which will mature in ten years.
After much consideration, I realized how sad the situation actually is. Not only does my mother want nothing to do with me or my life, but I have also been disinherited. Paralyzed by imagined feelings of guilt and grief over my brother, I had agreed to this arrangement back then.
I really like and appreciate my mother's partner/caregiver/cohabitant and I wish him financial compensation for his care. However, he comes from a socially disadvantaged and low-class family and has not had any children of his own so far. If he were to have children, it would only be a topic in the distant future if he turned to another woman and started a family with her. That's why I asked him to have the documents amended by a notary in a way that the house would revert to me or my son in case of his death, if he leaves no biological or adopted children behind. He promised several times to look into it, but has not taken any action in that direction yet. I am slowly coming to the realization that he may not have any intentions to do so, and even worse, that he may have ulterior motives. This is all very distressing to me. I do not want to argue with him, but I also do not want the house I grew up in and spent many wonderful years in to be inhabited by his relatives in the near or distant future, whom I have never met and do not wish to meet.
So here are my questions: Is it possible to contest the transfer of ownership or to threaten legal action against my mother's partner? What would be my legal share? I would prefer to forgo any financial compensation and instead