How to read tablature? 
Intro - strum or fingerpick, x2 -:

    Ab             Fm            Db               Eb 
xA|-------3-----|-------0-----|-------0----0~-|-2-----|
xE|----0-----0--|----0-----0--|----1------1---|---3---|
xC|-0---------0-|-0---------0-|---------------|-----2-|
xG|-------------|-------------|-2-------------|-------|

Verse:
Ab               Fm                 Db 
I remember your bare feet down the hallway
  Eb                    Ab 
I remember your little laugh
                 Fm 
Race cars on the kitchen floor
        Db            Eb                         Ab   - Intro part - Fm  Db  Eb 
Plastic dinosaurs, I love you to the moon and back

Verse
Ab               Fm                Db                 Eb                  Ab 
I remember your blue eyes looking into mine like we had our own secret club
               Fm             Db             Eb                       Ab 
I remember you dancing before bed time then jumping on me waking me up
                     Fm 
I can still feel you hold my hand
Db           Eb                       Ab 
Little man, from even that moment I knew
                           Fm 
You fought it hard like an army guy
  Db                      Eb 
Remember I leaned in and whispered to you

Chorus:
Db                  Eb 
Come on baby with me
                    Ab      Db 
We're gonna fly away from here
    Db       Eb          Ab     Fm  Db  Eb 
You were my best four years

Verse:
Ab              Fm                  Db 
I remember the drive home when the blind hope
          Eb                      Ab 
Turned to crying and screaming, "Why?"
                        Fm 
Flowers piled up in the worst way
             Db                   Eb 
No one knows what to say about a beautiful boy who died

Verse:
Ab                    Fm 
And it's about to be Halloween
             Db            Eb                        Ab 
You could be anything you wanted if you were still here
               Fm              Db 
I remember the last day when I kissed your face
  Eb 
I whispered in your ear

Chorus:
Db                  Eb 
Come on baby with me
                    Ab      Db 
We're gonna fly away from here
Db                      Eb                          Ab 
 Out of this curtained room in this hospital grey
                 Db 
We'll just disappear
                  Eb 
Come on baby with me
                   Ab       Db 
We're gonna fly away from here
    Db       Eb         Ab 
You were my best four years

- Intro part -

Bridge:
            Db                Eb                Ab 
What if I'm standing in your closet trying to talk to you?
          Db                Eb                    Ab 
What if I kept the hand me downs you won't grow into?
              Db                   Eb             Ab 
And what if I really thought some miracle would see us through?
                Db           Eb                Db           Eb - once -
But what if the miracle was even getting one moment with you

Chorus:
- Db -               Eb 
Come on baby with me
                   Ab       Db 
We're gonna fly away from here
                  Eb 
Come on baby with me
                   Ab       Db 
We're gonna fly away from here
    Db       Eb         Ab 
You were my best four years

Outro:
Ab               Fm                 Db 
I remember your bare feet down the hallway
  Eb                        Ab 
I love you to the moon and back