Mom and little boy having fun & eating by the lake.
A mom and a son spending time together on their weekend supervised visit.
A boy is not assumed to be someone's son.  Having fun and eating does not imply that it is a weekend supervised visit.
Having fun and eating by the lake does not imply that they are on a weekend supervised visit.
The little boy was never implied to be her son. It wasn't stated that it was a weekend supervised visit.