First of all, as someone who majors in writing dialogue, this seems like it would have been extremely difficult to write. And you did it perfectly. Amazing. Not to mention how much I already like mute characters.
However, I am curious as to what the traumatic events were that caused Cas and Dean to stop speaking. Poor babies :(
Congratulations on writing the only thing to have a good plot, is well written, and had me captured within the first paragraph.

Oh my god. Who would have ever thought that a fic with no spoken lines would speak to me so much? I'm in love with this fic. It's just the right amount of fluff. And I've never heard of that book before but I just looked it up and it's so cute.

This was beautifully done this is possibly the best one shot with epilogue I've ever had the fortune to read thank for putting it up ! Also the children's book "and tango makes three" was a perfect touch :)

I was not prepared for that ocean of feels. I don't know anything about selective mutism but this seems really heartfelt. I don't know how to compliment you better than that but believe me you deserve all those compliments.

What are these? Are they... tears? What? I don't cry at fanfics. I don't. I don- oh, well. One exception can't hurt. Great job! Very sweet and touching. Keep writing. :)

This is a really great story, and what you did for Claire was very lovely.

Hi. Claire again.
I just want to thank you again. To thank you so. Much.
This is all i could have ever asked for for James, this was absolutely perfect. The peace, the content. The little girl Mary, and James as their son. Me as the niece. No one has ever done something so sweet for me. It was perfect. Utter perfection.
I loved the quiet wedding & proposal. James & I used to talk about what I'd be like I we got married. He always wanted something small too, something easy and light, but filled with love. This encaptured James in every way, even if you didn't realize. Tonight, you sincerely changed my life. I have been in a deep, dark, ugly depression. Now, I think I can get through it. I can. I know I can. Things will be ok, James will always live in my heart, and now James will live in your story. It's kind of a re-birth, you writing him in this. As Dean & Cas's son, the boy can grow up and live a wonderful life. Just like James always should have. Amazing amazing work.
Also, thank you for that end note. It helps to know someone cares, someone understands even slightly what it's like. Nothing could make me happier right now. Thank you so much. I cannot tell you what that means to me.
Claire

Hi. My name is Claire.
And you just sincerely made my life.
Lets start over. When I was little, I had the best big brother in the world. He would bake cookies with me and play games and read me stories at night. He would hug me and protect me from all the evil in the world. He was my best friend. His name was James.
November 3, 2010. James and I were relaxing at home and watching Home Alone. Ironic, we were home alone. James heard a noise and pushed me in a closet. Next thing I knew, a man was standing there. My 14 year old brother just looked at him. He screamed at James asking him where my mom, dad, and I were. "Where Jake, Kelly, and the little bitch, James?" He refused to say anything. Then he was tied up. The man found my parents and brought them in the living room. He brutally tortured and killed them in front of him. I remember nothing, I had passed out due to fear. I woke up in the hospital. James apparently, had gotten out of his bonds, hit my dad's old work friend over the head, and gotten a hold of a phone and called the police. He changed that day and became mentally scarred for life. He didn't recognize me. He didnt talk. Now I live with an aunt, and I am as happy as I can be. Which sadly isn't that happy.
You see, James stopped talking. He didn't respond to anything or anyone, exception of fear at me. I looked too much like Mom. One day he killed himself, hung by bed sheets.
Worst day of my life.
Now, im not asking you to take this story down. Not in the slightest. In fact, it reduced me to tears. This is the ending I always wanted for James. I hoped and prayed he'd get better, but he didn't. I didn't. But this is my version of him recovering. He could have found love, someone sweet and kind. He could have gotten better. He didn't, but Cas & Dean did. And that's ok. That makes me feel good.
I hate to ask, because I know you are such a good writer, but could you add a part two to this? Where they get completely better. Just, maybe? I always wanted him to get married and have kids. Adopt one or two. It's all I've ever wanted.
I just want to say thank you. This is literally the happiest I've been in a long time. You have offered the best recovery chance. You help me remember James. You help me think of him, how things could have been.

Thank you. So much.
Claire

I don't know much about mutism either, but it's a really adorable story! I like the idea, and I think the way you wrote it was really interesting and creative. Overall, very cute fic.