My friend was raped & we need some help with the legal part of it...?

so, heres what happened. she was 15 & he was 18. they had non consenual sex. & it got reported the night of the event. they took her clothes & his bed sheets for evidence, & she was interviews & so was the guy. we just wanna know what exactly might happen to the guy. it happened three weeks ago & she still hasnt been notified or anything about what happened. her parents have the case number, & they call almost every day but the detective signed to the case never answers. what we wanna know is what normally happens to the guy with this kind of case. how likely is it that he got arrested? she saw him a week after the attack so if he did get arrested he wasnt in there for long. it wasnt a violent rape either so that might have a part in what happened. we just really wanna know how these processes normally work, what normally happens with it, whats likely to happen. do they normallty take it to court? is he gonna end up on a list? etc, ...please help!