Did my 13 year old brother run away?

My little brother tends to lie so I really dont know if he is telling the truth or not. He is living in a group home and he just IM me on facebook telling me he ran away because he got caught smoking in his room. Were in the seattle Wa area and he told me him and his friend went to Cali on grey hound. Does this sound realistic at all? Like how would he even have that much money. I asked him where he was and he said are you going to tell the police. He logged off after I asked how he paid for it. I just dont know if this is true or not. what should I do I tried calling my gma to ask her but no answer. He also told me maybe a week ago that he asked his social worker if he could move in with me and my family I am only 19 and he said his social worker would call me to ask about it. I havent gotten a call yet and I didnt believe that one