looking for experienced carpenter advice

[Jeffrey Gagnon]

My father is a life long carpenter and he has a large problem with the photo i have attached. i was wondering if anyone could give me input on the situation. Is this an easy fix or is this something that could get pricey the issue he has is the 2x4's supporting the roof. any input from experienced carpenters is much appreciated. my dad has incredibly high standards for things so i am trying to get a second opinion.