He played really well at Flamengo the 6 months he was there and he’s pretty much become a cult hero for their club, but he was surrounded by a South American All-Star team during his time there and playing lesser competition. In his previous European stints he wasn’t an elite level player, and I don’t think he’s become that much better in 6 months.
But Arteta worked with him previously at City, so he clearly sees something in him. I just wouldn’t have very high expectations.