Will was not certain how to interpret the comment about being the stranger everyone gets to know. It implied many things, some of which were obvious and others more... creative. The boy was extremely sensitive to the nuances of others and thus could draw oddly accurate conclusions most of the time. But he was far too tired to link puzzle pieces together to form a picture of who--- or what--- Azrael was.
Ice cream was most likely not the prime choice in winter. However, a child unsupervised was prone to irrational decisions. Ice cream was comforting: evoking both physical pleasure and emotional calm. It recalled memories of better times. Perhaps he was selfish for dragging along some poor man that did not understand what he had signed up for. But at the moment Will's discomfort with being alone overrode that of his altruism. Against all logic and history Azrael made him feel protected.
It came as a surprise even to himself that Will placed one delicate hand in the man's much larger one. Despite the other's kind demeanor this was still a stranger. But Will was deeply tired and still so scared. His body was brittle and anyone that could hold him together was welcome to try. A small, tremulous smile of gratitude was offered for the assistance. "Thanks. You don't have to do this. But... I'm really glad you are."