Watery eyes in a child is most often due to a blocked nasolacrimal duct. Normally the duct fully opens by the time a child is 12 months of age.
Squint surgery in a child is performed to realign the eyes so that they appear straight. Squint surgery can also help with maintaining or restoring binocular vision and to a small extent help with depth perception.
A droopy eyelid in a child is most often an isolated condition not associated with any syndromes or systemic conditions. It is important to make sure that the visual axis of the child is clear, to prevent the child from developing amblyopia (a lazy eye with poor vision).