Hello. I'm so sorry for your loss, what a beautiful thing to have your son live on through his music. My name is Martin, I'm new to Freelancer and was looking to experience what it's like working through this site when I came across your post. I've been playing guitar for more than 10 years now, and piano for about 3 years, and I think I'd be capable of transcribing all of your son's songs in about a week or two. I promise to get everything perfect and listen to every single song so that you can make that songbook. If you'd like me to work on this, please contact me with more information and I'll be more than happy to help. Again, sorry for your loss and I hope you can finish the songbook, whether or not it's through me.
Hope to hear from you, Martin.