I don't really know but this may shed some light.
I am so proud of my son Matthew. Yesterday we met our new Russian neighbors. Matthew went to the door to ask if their 10 year old son wanted to play. We already knew that he was non-verbal autistic but Matthew insisted because he helps another autistic kid read in class. He says that they think the same thoughts but have problems communicating, but he is the same as Matthew and wants to play. They played for about two hours...Matthew talked to him the whole time and held his hand to show him he was a friend. They had a ton of fun and soon all the other neighborhood friends showed up and had a blast.
The mother told me today that she lived in another neighborhood for years with a bunch of kids and not once did anyone ask him to play. She said it bought tears to her eyes and posted it to all her friends on FB. She was in tears telling me which made me tear that my son was kind and that her son hadn't experienced that before. She thanked Matthew which was not necessary. I told Matthew that a kind heart is worth more than anything in the world. I love that he sees no difference in others. The golden rule. I have a great kid and love hearing how he made some mom's and son's day! Bragging rights over! Posting a picture from the other day...he loves life and just rolls with it!
Now that i think about it, perhaps having food allergies and being bullied at school may have played a part in how Matthew likes to help other kids.