I won't talk about if it's transcribed correctly or not, because I don't know the piece...
However, the part you've mentioned is actually 'only' a 10th.
There are a lot of people who can reach a 10th in certain key signatures, me included:
This 10th for example is very easy for me to reach, in the key of C I could even get it up to an 11th:
If you can't reach a 10th, just roll the chord/notes from low to high. There are people with small hands who can't even reach an octave. They also just roll the chords. Of course in this situation the sustain pedal might be helpful to not lose the lower notes after you rolled them ;)
If done properly it still sounds good, just a bit different.