IDGAF ABOUT THOSE KIDS STFU AND POST OC PLEASE

I have a suspicion that my 2 cousins are fucking bros...They literally go everywhere together, only hang out with each other, post each other on Instagram and go to the gym together where they click thirst trap pics of each other. Haven't seen anything between them irl but they could be good at hiding it

Then again I don't know if that's how close relatives are supposed to act with each other, I am an autistic incel creep who's probably projecting my my girl cousin's lust onto the guy (she's pretty hot tbf)

Is there anyway to find out other than catching them in the act? That probably won't be possible cause I live on the other side of the country