Mike is the living example that pirates have their healers! Try to argue his faith in the Spagetti Monster and you'll probably end up earing long and tedious descriptions of the Pastafarian cult and how it perfectly blends with the Pirate culture of freedom.
His role in the party is the inconsistent combination of an archer and a healing bard/spellcaster, requiring you to manage not only his holy powers , but also a large array of buffing potions & songs and a strange attitude to explosive mixtures.
Main is Grit
having him as a leader is a wise choice if you wish to boost your party resistance to states and/or critical chance.