How would i know if my 15 year old brother is gay?

hes 15 years old and pretty weird but everybody is not everything is related to being gay... well he always acted girly when he was young, wenever me ( im 18) and my 13 year old brother used to play when we were younger the brother im asking about would always want to be a girl, one time we were playing 3 ninjas and we needed mybrother to be one of them but he wanted to be a girl instead and wudnt play unless he could wear a towel over his head like hair.. he always wanted a wig... the way he talks and acts is gay . hes fat and like 5 ft tall... and always shits his pants ( just adding random details i can think of) he always draws girls like the anime styles and even draws them naked but with no or just the shape.. all his friends are girls, he wants to be a fashion designer .. he throws like the biggest .. when he was like 5 we put him on a soccer team the whole game he didnt even go after the ball he was just off in a corner spinning around becuase his shirt was too long and was twirling it like a dress... when he was young we wud always catch him naked in a closet lol .. everyone in the family knda thinkds his gay but hes so like quite about ual stuff like his aual or sumthing but hes not its like he doesnt nkow if hes gay or is just hiding it i dont know it just seems like it i dont know u can just kinda tell the difference i meen the 13 year old brother is like me and my older brother lkes fighting and guns boy **** but the 15 one is different i can tthink of much right now obviously its easier to tell if u lived with him....anyone grew up with a gay younger brother id be glad to hear ur story how u found out or if neone has any ieas how you can tell... its not much my business i kinda make fun of him becuz he seems like a but i be supportive if he came out of the closet its lame of ppl to hide there uality like its wrong but its coo if ur open nfree about it ... i know its not my bidness 100 % i just wanna hear wat ppl have to say thanx sorry for long post just typing as i think