He won’t tell anyone about me

So my cousins son is two years younger than me we speak every days and he comes to my house nearly every day he has my number saved as something else on my phone and won’t tell anyone he comes his other brother comes to my house and his mam knows so why won’t he tell anyone he comes to mine and speaks to me we’ve grown so close where like best freinds but he won’t tell anyone and nobody knows why we come from a Asian background and his family are Muslim