Was my dream a call for help or a sign...?

My baby brother, who is 18, ped on Wednesday, Nov. 20th... Tues night He came to me in my dream! He interrupted my first dream to tell me that he's gone. I only saw white mist and my bro standing there looking down with a smile. I said, " Bro, is there a heaven?" He said, "Yes, I am here!" Then he was gone. Come to find out, he went into cardiac arrest the next day... and we couldn't save him. So, now he's gone. I am searching for realistic answers, this is very serious. Do you think It was a sign to save him.. like a cry for help? Or was he telling me that he's okay, not to worry? Please respond... I need a little bit of closure.