What is up with some creepy uncles and kids as well ?

So I (22M) was travelling by Gundavali Metro in Mumbai the other day. A kid (10M) came and sat besides me, Now here I was staring in my phone so. Then after some time an old uncle (65M) came and sat besides him. Now the Kid seemed to know the uncle. And he then took that kids hand and kept it on his lap, very close to his privates. That Creeped me out. I saw that man holding that kids hand and was doing something, Maybe some bone Cracking thing. And the kid was enjoying it. Then later that Old uncle placed his hand on that kids Lap close to his Privates, and the Kid was smiling and giggling and pressed that uncle's hand deeper in his private area. Then That just crossed a Line. I asked the kid does he know that uncle, Or is that uncle your Grand Father. The kid said no. Then I asked Come on the other side of me, To this the kid said no. While all this was happening the old uncle was staring at our convo while smiling. Felt Like Should p*n*h his Face. Then I asked him again is he Your Uncle, The Kid now Said yes. This time I Insisted him to come on this side, The kid got up but then the Old uncle got up as well all while holding on to that kids arm, to which I Asked him if he knows the kid to which he smiled and said, Yes I am His Uncle. Then immediately 30 Secs Later my Destination Arrived and I had to Get off. I don't Know But I still do wonder what was up with them. it was 11 30, (I got on the Last metro from Gundavali at 11:00 P. M.) So I couldn't Even Find Much Staff so I could Complain becuz the Station was Shutting off. I Just hope the Kid is Safe. I felt so Defeated. Becuz there was nothing I could Do. The Kid and Uncle were Smiling after that as well. It's Weird.