Attended Hogwarts (Either hufflepuff or ravenclaw)
Went on to study magical medicine, and eventually enrolled in muggle medical school
Fought in the Battle of Hogwarts, and despite his vow to do no harm as a healer and a doctor, he took lives to save others. He moved to australia after the war, leaving family and friends behind to make a new life living as a muggle. He didnt touch his wand for several years.
Met his future wife somehow. Neighbors maybe? Some kinda fanfic coffee-shop meet-cute kinda deal. IDK It’s up to you, cause the way the story goes is that Amanda is a muggle, and they both like to travel, carefully avoiding England, Wales and Scotland for a while, until they decide to get married and have an adorable baby (Spoilers… they name her something incredibly Welsh that will surely make her stick out… because they are those sorts of parents… not really) so then they have this adorable child to travel with too. By the time the child is 6, her passport is more full than most adults her parents age. ANYWAYS
They were living in Germany for a time when Amanda passed (Siwans profile says car accident but that can probably be adjusted should you wish), they lived in Japan for a while, and then back to England. They moved back to Australia recently to finally settle down and he wants to give his daughter some stability.
Personality (though I think all of the travel might have made a very utilitarian and minimalist kind of life-style common for them… though recent relocation and the intention of making it permanent might have drove Rhys to buy a large house with an on property apartment for grandparents. The house is weirdly empty during the week since SIwan stays at school and only returns every other weekend while school is ongoing) and all the specifics of him are completely open. Check Siwan’s profile for major recent dates for a vague timeline. Poppy and I had an idea that Rhys and Ash were good mates in school (so Hogwarts time for them)