If he is eating the 2 patties - serving size for a 5 lb dog - then I think he is getting enough food. So, I would just split his 2 patties up between 3 meals.
As for when you go back to 2 meals - I don't think there is a certain age to go to 2 meals. It is just when ever he is big enough to go all day on just breakfast. In a couple months you could evaluate again or ask your vet. I always free fed so I don't have any experience with that part.
Oh and welcome to YT!
