I may be being overly optimistic, but one of the reasons I’m confident on the outcome of Haru’s character arc is that - so far - it has been quite the parallel to Rin’s in S1, imo. Just inverted.
We have things like their nightmare sequences and even the pacing of the happenings to draw that home, but beyond that:
Rin pursued what he thought he wanted. In episode 7, he achieves his perceived goal, turns his back on the past and thinks he’s ready to move on.
Haru is running away from what he thinks he doesn’t want (going pro). In episode 9, he fully turns his back on that unwanted future, faces the present and looks about ready to return to his status quo.
We know what happened to Rin - he realized that what he pursued was actually the opposite of what he truly wanted. But it took an intervention from Makoto, watching Iwatobi swim the relay and an intervention from Rei (an outsider, someone with more insight on Haru than on him and who thus allowed him to get the big picture) for Rin to realize his true wishes. Cue Haru being able to reach out to him.
(I’m over-simplifying it, but hopefully you guys get the point hahah)
So following the way their story-lines have paralleled each other so far, I do think it’s more than likely that the very same thing will happen to Haru.
That - after an intervention from Makoto, something else (the equivalent of Rin watching Iwatobi swim together in EP 8), and an intervention from Sousuke (an outsider from his group of friends, someone with more insight on Rin than on Haru himself) Haru will realize that what he has been running from may just be what he truly wants, after all.
Cue Haru being able to face Rin’s light without being overwhelmed by it.