I am confused

I am a 15 yr old male and today I was buying chips with my dad and siblings and a class mate let's name him m for this post who was a bully to me as I seemed like an easy target as I is bigger than me and because I stutter as I result I never thought anything of him as he felt like the typical burnout with his gang of friends for the past 2 years without interacting with him or his group of friends avoiding them when going out if I spot them and tell my friends to just leave them and go. Since the end of the last school year I saw he was trying a bit more than usual in classes and was trying to pray more with the other students and even told my best friend stuff I don't know if it was a good idea to share with me or not like him trying to stop porn I started trying to help him more in ways like reminding him to join us in time for prayers and just not fully avoiding him this is because I did feel a sense of him being like me as I did struggle quitting porn and also having a time of my life where I was struggling in school but now got on track to being one of the best ones in my class. Today was different tho as I went with my father and siblings to get some chips before heading to school I saw him buying something he bought it and left quickly I thought he just left quickly as he didn't like me or as usual just not wanting to say anything but when I told my best friend that he asked him jokingly how was the coffee he remembered seeing me and apologised for not saying anything saying he didn't want my dad to think I was friend with a delinquent like him self. Idk if it the sense of insecurity I see in my self or something different but I feel like I should have said something. What should I do