My autistic friend believes that his best friend abandoned him, what can i do to help him?

My friend, Tommy, is autistic. He has asperger's syndrome. He was really close to his best friend, whom he called Eevee, after one of her favorite pokemon he told me. He and Eevee would talk everyday, until recently. Apparently, one of his roommates upset her and she hasnt talked to him since that night. He has been very upset and worried about her. Now he thinks she abandoned him and doesnt want to talk to him anymore.. He keeps saying that she said she wouldnt leave him. What should i do to comfort him if she does no longer want to be his friend? Should i try seeing if he will let me contact her?