At 16, you can certainly be in love ~ you can even get married ~ but I agree that the teen years can be difficult, because of hormones, etc. Everything is more intense. This can make love even more wonderful or even more painful. Often what seems incredibly important at 16, no longer seems so at 26, for example.
I think that a 16-year-old probably would know if she were lesbian or bi-sexual by this time, but, it is also common for people who are not homosexual to have homosexual 'crushes' during the teenage years.
This whole situation does sound very confusing though.
I hope it works out well for Mike's friend because, as I said, teenage years can be difficult and it may be hard for this girl to talk about such a personal and emotional subject. She needs support from her friends.
