Time passes.
Minors can't be emancipated in New York until they're sixteen, so Lev is hiding in Stark Tower for now while Asher bribes the cops to look the other way. (Asher makes various grumbling remarks about how for once the cops are being bribed to overlook rescuing an abuse victim, instead of the other way around.) Jarvis handles the paparazzi.
Lev's still very thin, but he's not going to walk any catwalks any time soon. Asher's fridges are full of calorie-dense food: peanut butter fudge, avocados, protein powder, whole-fat milk. He lets his hair grow out, partially to make him look more different, partially because he thinks he looks better that way.
Asher has the hands-off attitude towards education of a person who was homeschooled and attended college at fourteen. Lev takes online classes and reads textbooks, supplemented by occasional tutoring from grad students at NYU. For the first time since he got his power, the classes actually go fast enough. The ever-present book of sudoku is replaced with a scrap of paper on which he proves theorems.
Lev doesn't have the background knowledge or the interest to help much with Stark Industries, but he spends a bunch of time figuring out what various supervillains are doing and also working with the Yinsen Foundation. His list of courses becomes lighter on science and heavier on social science, although he still loves and is interested in everything.
Sasha and Lev go out on dates. They can hold hands in public and kiss. He brings Sasha flowers he picked while Sasha was at school; he writes Sasha letters about how wonderful he is and how much he means to Lev; he learns first aid so he can treat Sasha's Spiderman wounds more easily.
Lev's bedroom is soundproofed and they can have sex as noisily as they want. After the third or fourth time they've had sex, he has enough training data that he can just have his power running the entire time they have sex; it has advantages in terms of always knowing exactly how Sasha wants to be touched and what Sasha wants to have said to him, and disadvantages in terms of having to have fudge by the bed so he can eat as soon as they're done.
Lev is willing to do Sasha's homework for him but he really wants to explain everything to Sasha. It sometimes takes him a moment to remember which things are and are not obvious, but once he knows his explanations are generally very good and he never seems impatient with Sasha for not getting something. He does, however, regularly wander off onto some unrelated topic that Lev happens to find interesting. (Everything in the world, according to Lev, is interesting, especially anything that has to do with people. People are the most wonderful and fascinating topic on the planet and he wants to know everything about them.)
He is so very, very happy.