There are things that could be done, if he wanted them done.
If he has confidence and isn’t worried, and has high self esteem such that he is able to ignore it all, let him be. Make sure other family members do not criticise appearances and definitely be all over dd if she comments about him. Let him know he can talk to you, always. He sounds a lovely boy.
It’s always good to be mindful about healthy living, however, not positioning things as diets but encouraging sport, exercise, making sure the meals you offer are well balanced etc. Good attitude to snacks, for example. He will grow soon, a lot of kids gain weight before stretching out.
Equally, if he does say something and it’s within your power to change it, I would. The glasses, when they need changing, I would maybe suggest a style or thinning of lenses just because it would be a change, or look nice, or more grown up. Same with his ears, know the options, and if it comes up then you’re ready to advise.
My own teen years were a nightmare of bullying thanks to an aspect of my facial appearance that my mother refused to let me do anything about, despite being easy and cheap to alter. I was terrified of her, if I ever mentioned it I was vain, a sheep, pathetic etc. The second I left home I sorted it and vowed I would not take that shit again. My own dd has the same thing and as soon as she said other children had started on at her, I was ready and we got it sorted. Her personality at school changed overnight. It’s been 3 years now and I doubt anyone would even remember how she looked before. She wanted it, so I was happy to make that happen for her.