Mix pineapple, sugar, and eggs together in a saucepan; bring to a slow boil. Reduce heat to low and continue cooking until mixture thickens, 3 to 4 minutes. Remove saucepan from heat and stir gelatin mix into pineapple mixture. Set aside to cool.
Line a pie dish with enough vanilla wafers to cover bottom.
Beat milk in a large bowl using an electric mixer until thickened, about 3 minutes. Stir gelatin mixture into whipped milk and pour over vanilla wafers. Refrigerate until set, about 8 hours.