A guy that is being friendly doesn’t put himself in too many one-on-one situations with you.
When there are one-on-one situations, he keeps them relatively short.
As he talks to you, he keeps conversations safe and avoids transparent flirting.
There are occasions where he talks to you about other girls.
He is into either girl for what she fulfills for him specifically, and to that extent, he is into either one of them at one time.
It is possible for a guy to look to two girls as equally important to him in reference to what they do for him individually.
One girl is game to do any activity he is into, including guy-centric activities such as playing sports with him, which makes her a girl that is like one of the boys.
The other girl is quintessentially feminine, looks really pretty on his arm at a social event, and boosts his social credentials as a result.