I think you can only have 6 to 8 oz of seafood per week. Check with your doctor recommendations.
Seviche uses the lemon/lime juice acids to cook the shrimp so it's not necessarily raw like sushi but its not fried, grilled or boiled either. I would ask the cook how they are preparing it and run it by your doctor as well.
Seviche? As long as it isn't raw I'm sure u can eat it