In your position I would not take your DS. As you pointed out, it may be too soon for grieving parent's to be faced with their child's friends running around. I wonder if that would compound their loss and cause more pain (if that's possible). Whilst I am all for children at funerals, children's funerals are often filled with more emotion than that of an elderly person whose time has come. I would worry about the impact on your DS of being in such a highly charged emotional environment, particularly given he is probably still too young to fully understand why people are so upset.

I am sorry for your friends loss, I can't imagine the pain they must be experiencing.