@BlackHoxton That's possible, though keep in mind that like 2 chapters ago there was an implication the dude is tracking Kauro through some sort of GPS thing that Kauro doesn't know about and what happened at the end here, 'who' he's crushing on doesn't really matter.
Heck, going even a bit more speculation I think the dude might have caused the sister's death by confessing to her, getting rejected, then pushing her due to emotions which lead to her fall (he said his love was unrequited then recalled the scene where he and Kauro were looking at her body, yet Kauro hasn't shown any strong emotions/memories to that scene suggesting it was extra impactful to the childhood friend), I could be wrong though.