Repeat evaluation. Eye crossing can return as you age. Strabismus surgery is rarely permanent and often needs to be repeated later in life as eyes can decompensate. See a pediatric ophthalmologist for a reevaluation. Repeat surgery can be performed if necessary.
Not much. A "lazy eye" is healthy with poor brain visual development. As we age, the eye should appear similar to the normal one but the alignment may be off. As long as there isn't any underlying eye disease such as cataract then the eye should appear normal.
Nothing. Once visual development is completed, the lazy eye just ages at the normal rate and can get the same eye diseases as a regular eye such as cataract. Uncorrected strabismus can worsen over time.