Can anyone help with making a shiva call?

When it comes to shivah, the only people who actually sit shivah are direct family members; parents, siblings, spouse, children. Everyone else attending shivah is there to provide support for those in mourning. Normally, children move between spending time around the family and going off to different parts of the house to do normal kid stuff. I'm sure your sons' friend will appreciate having them come spend time with her.

In Judaism, we do not have flowers at funerals as funerals are associated with life and celebration. The tradition is to bring food as the community provides for those in mourning. Even though the family is not Orthodox, if you do wish to bring food, I'd recommend that you try to bring something kosher. You never know if other family members are religiously observant. If that's too difficult, fresh fruit is a good alternative.

Yes it would be appropriate for your son to play with them. I recommend you bring food, as that's traditional--bring something round like hard-boiled eggs, bagels, lentil salad, etc. Do **not** bring flowers.

seek some counsel from someone who knows the protocol( contact a local synagogue)..... but in general...... as long as you are of the right motivation.... and respectful of the customs.... then you visit would be appropriate