Translation of fraulich in German-English

My brother moved there last year. He met a woman and went after her. After six years they have broken up, but he no longer wanted to return, because he has settled down in his new home. I am visiting him once a year.
I've been working on and off on the dictionary during the entire week, and I'll spend some more hours on it this coming weekend. Sometimes he would get a bit mixed up and use formal Castilian sometimes instead of informal.
I need to learn a lot of Spanish because I want to study at the university of Madrid. In Switzerland, I studied law, but after 2 years I have switched to medicine: to help people, rather than you know....