Dogs, and even puppies, won't starve themselves if they are otherwise healthy. Find a food that YOU think is appropriate for him, (you will get as many suggestions, some with militant supporters,
as there are Havanese on this group... the decision is ultimately yours) and then, unless you think it's not agreeing with his digestive track, STICK WITH IT. Put it down, and wait 10 minutes. A healthy dog can easily eat his meal in under one minute, so 10 minutes is AMPLE time. If he doesn't start eating and stick with it for that period of time, pick it up and put it away. Do NOT offer it again before the next meal time. No treats, no nothing. Do the same thing at the next meal... and the next. He could skip for a day, or even a bit longer. Assuming he's healthy, he WILL give in.
Havanese are EXCEEDINGLY good at talking their owners into the idea that they are "picky eaters" and need to be coaxed with increasingly "better" options. If you fall into that trap, they can keep it going indefinitely. "Just say no".
Kodi, as an "only" went through a "picky stage" as a puppy, and based on good advice here and from his breeder, I hardened my heart and waited him out. Pixel did it a TINY bit. Panda, who came into a multiple dog house, where there was always someone willing to eat anything she left, NEVER played the "picky" game.