Balotelli faces his former club for the first time today.
"My friend Mario has always been a Milanista, so it's no surprise he is there now. Milan was his dream," Matrix told La Repubblica newspaper.
"Do you know how many times I had to chop up his Rossoneri socks in the locker room? His Mum bought them for him and he would wear them in training, so I'd sneakily cut holes in. He laughed like crazy.
"We send each other hundreds of text messages per day, so yes, we're still good friends. I want to say I am really proud of him. Of course I won't stop our friendship just because he went to Milan.
"Do I need to give him advice on how to behave? Look, Mario never hurt anyone, he's a really good person. He simply likes enjoying himself and is still a big kid.
"The other night at San Siro I saw him dancing in the stands with Robinho. That is Mario, he lives life like someone who grew up in the streets and I love him for it. He has fun in a healthy way, not like those who act up, get drunk or ruin themselves physically."