Alexi was born into a regular pureblood family, in London. His father was an auror, and his mother, a healer. They met after his father got sent to St. Mungo's after getting an injury in a fight with a former death eater. Shortly after giving birth to Alexi, his mother decided to retire from healing and to be a traditional housewife, taking care of Alexi, and teaching him everything he knew about healing, and morals.
When Alexi became of age, he went to Hogwarts, and immediately felt lonely, because he wasn't able to see his family too much anymore, and he didn't make friends. He was found in his books way too often, compared to other young wizards and witches, who were flying, duelling, etc. Throughout all of Hogwarts, without any problems, as in the Dark Lord, etc., there wasn't too much glamour or action other than the occasional Slytherin who felt like blowing up his/her potions. Alexi did, however, volunteer at the infirmary, and got a lot of practical training in his aspired position, as a healer in St. Mungo's, just like his mom had been.
Alexi graduated Hogwarts, to be shocked to find out, almost too coincidentally, that the Dark Lord had risen up again and took the reins of the wizarding world. Alexi, naturally, was scared, but he tried to make up for that by doing dangerous stunts, like mountain climbing. Ever since graduating, he also got a job as a healer, which he was ecstatic about, but he never really got to see his family face to face anymore. All he could do was write letters, because ever since the death of the famous Harry Potter, too many people were getting injured and sent to St. Mungo's.