I'm so happy you got Max to eat
Usually softening their food is a good way to go. Even our little Peanut that we had, he was atleast a year and half old when we got him and we had to soften his food when he first came to live with us. Whatever way you do it, with water, canned food, etc..,
it's so much better than them going hungry. They are so tiny, it's extra important that they eat.
I would get a tube of nutrical and keep it on hand. You can buy it at any pet food store.