Esther, although I no longer work in the field, I am a liscensed funeral director. Some of the most meaningful and healing funerals we had were when the family participated in some way. We called them "Life Appreciation" services, because they're about remembering the person in a positive way.
So if Kevin is up for it, I encourage him to speak. There are lots of other things that make a service unique -
Music - instead of the same old stuffy hymns, how about some of the music Braeden likes?
Photos - collage of pics of Braeden, his family, pets, toys, trips, etc., near the book where people sign in, or near the casket, or both.
Movie - yes, you can show home movies or videos in the funeral home or church.
Items - you can exhibit a special toy(s) of his, drawings he made, books he liked, etc. You can also put things in the casket with him, like a teddy bear.
Eulogy - people speaking about memories of the child, etc. Best if the speakers practice this out loud a few times. It's mighty hard standing in front of a crowd to speak when your heart is breaking.
I'm so sorry this is happening. I wish you and your family strength.