Alejandro!
Hey Buddy! I know where you are at in dealing with your family situation, remember it’s only their present state of reality, avoidance is never the answer and NLP used in a clinical or therapy model only works for clients who pay upfront and have a burning desire to remedy their current thought processes. Children are very instinctive and work from a Values level 2,3,4 mindset. They believe uncritically all information they are fed from the leader of the tribe. i.e. Thier mother.
I have 4 children 13,10,8 and 5 Divorced 5 years after a 10 year marriage. Thier mother was pregnant with the 5yr old when we divorced and it was the seeing of a Master Practitioner for couples therapy that got me into this.
As the children age and notice your emotional stability they will gravitate toward you naturally. Also being a father figure it is in complete congruency for you and the children to have deep and meaningful conversation, whenever we are riding in the car we converse about topics like school and friends openly this allows me to get a feeling for where each of my children are at emotionally and consciously which are almost never on the same page. So I spend a lot of my time asking leading and probing questions that get them to open up about thier thought process and I do this infront of the other children. It shows that I care deeply for thier well being and it allows the other children to begin thinking critically about how they choose to approach and participate in life from the perspective of self evaluation and behavior. I constantly preach the presuppositions of NLP before or after any discussion as a way of making it for them instead of about them. My children are developing very well.
The 5 year old has finally decided to start spending the weekends with us and leave his mother who held him hostage from me for the last 5 years, he was her pacifier. I never pushed the topic, always asked politely showed genuine interest in his interests and never allowed myself to show distain or disapproval of his decision to come with me or stay with his mother.
My suggestions are to spend as much time with them as you can independently of thier mother and while in her presence ask her if she remembers a time when she was happy and lead her through the process of being happy while you are around. Refrain for using any reference to NLP or any other modalities.
Simply be there and be there for the children this will change everything.
I hope that you find my words of value in your current life situation.
Aaron.