Don’t bother forcing it.
I’ll put it in simpler terms:
You can lose someone no matter how much you care or how hard you try.
The only reason anything would work is if both people are willing to be kept/stay/commit/pursue something, especially if this is going on for a while ...
If anything, maybe ask him why first
... If they really view you platonically, it's better you find out sooner than later. So, don't worry about any outcome :)