i need genuine advice (also pls don’t judge me) how do i let a guy know that i don’t want our relationship to go past friendship?

so im 16f and im in this friend group of ppl of all different ages and there’s this guy (or should i say boy?) 14m who’s been acting a little weird to say the least

this all started when people in the friend group started basically ganging up on him for talking a lot abt guitar, i rlly can’t stand when people are acting like hypocrites so i pointed out that everyone has their interests that they can talk abt all day and it’s not fair to make fun of someone who’s the youngest in the friendgroup

after that he started trying to get close to me which i didn’t mind but then shit started getting really weird

he keeps on sending me tiktoks that say something like “i love thighs so much” or “can i call u mommy?” and before anyone says it, yes i did make it obvious that i find that really uncomfortable and weird

and listen, maybe it’s because he’s autistic but i don’t think he gets that

last time we hung out we were all sitting on the couch playing mario cart and he sat next to me and kept looking back and forth from the tv to me at some he leaned closer and just started staring at my ear (wtf??) so i back away and he got real quiet after that

i rlly don’t want to see anyone commenting something like “well u lead him on” bc i rlly didn’t, last i checked wanting to be friends with someone and or not outright bullying them is not the same thing as flirting

also he is autistic so maybe just maybe he’s not doing any of this on purpose but i rlly need some advice

i would still like to be friends with him since he shares a lot of the same interests that i do and he’s actually nice but idk