Yes — honeydew melon is safe, hydrating, and gently sweet, seeds included.
Keeper's noteA good hot-weather hydration food. Like all melon, it's mostly water, so expect wet droppings and don't let it sit out long.
Why honeydew is good for parrots
Honeydew is another high-water melon: safe, easy to digest, and mildly nutritious with some vitamin C and potassium. It's less vitamin-A-rich than cantaloupe but just as hydrating and well tolerated.