Great material but wishing Mengestu would open up his characters a little more

The second section of Dinaw Mengestu's All Our Names continues with the braided double-plot: the Isaac chapters narrated by a young student radical in 1960s Uganda and the Helen chapters narrated by a social-services worker in conservative university town in the South or Midwest; the Helen chapters take place several months or so after the Isaac chapters, so if you put the two together you'll see that a young man (his nom de guerre is Langston, after the writer) gets involved in radical politics on campus through influence of a fellow-activist and outsider, Isaac; Langston gets beaten by police and hospitalized; essentially rescued from the hospital by Isaac and taken to a safe house, fairly luxurious, where he meets the head of a political movement - and we realize that Isaac is much more connected than we'd thought. At some later period, Langston - now appropriating the name "Isaac," arrives in the university town and Helen is assigned to his case - and quickly becomes his lover. So far so good, but I still hold to the concerns I expressed in yesterday's post: the Helen chapters seem very flat and generic and I'm beginning to worry about the Isaac chapters as well: after an initial burst of activity - the campus riots and the feeling of an outsider among the wealthy university swells is very well depicted - not much advances (so far at least) in the 2nd part of the novel. Isaac is meant to be a it of a mystery man, all right, and Helen knows very little about him - doesn't know his real name, or his background. But somehow Isaac should be revealing more of himself to us, his readers; for example, he arrived at the university in hopes of becoming a writer, fascinated by the writers who'd recently attended a conference on campus (he has a brochure from the event) - but there's not a word through the first half of the novel about what he's writing or thinks about writing, what he's reading, anything literary. We know nothing, from him, about his struggles to adjust to life in a new and sometimes hostile country- his hopes, aspirations, fears. I hope this will pick up but it's getting a little late in the game. Mengestu is a very clear and readable writer, but I wish he pushed his story a little harder - he doesn't trust his readers enough at times. In the 2nd section, Isaac makes a big "surprise" announcement to Helen that a good friend back in Africa has died and that his name was also Isaac - does DM think that we're surprised? Any careful reader has figured out some time ago that the young African in America has appropriated the name Isaac, that he's the unnamed narrator of the Isaac chapters.