My brother is 19 years old he has strabismus he went to surgery but he seems to get back like he was. is there is a way guarantee will work forever?

No guarantees: There are no guarantees in healthcare. How an individual's body responds to treatment is never completely predictable. Talk to the surgeon about your concerns. Good luck.

Difficult problem: To help surgery work, the brain needs to accept images from both eyes and work to keep both lined up.If one eye is weak and the brain turned it off (amblyopia), it is harder to keep alignment in that eye.If done in early childhood, there is less risk of permanent amblyopia.For that reason surgery when older may be more cosmetic than functional, and outcome can never be guaranteed.

Nothing is forever: Unfortunately, no surgery is guaranteed and often doesn't last forever. However, it depends on the vision in the eyes, what the previous surgery was, and what the misalignment is now. Adjustable suture surgery (where the muscles are moved after the initial surgery while the patient is awake) can increase the success rate.