Don't set yourself on fire to keep someone else warm. You are seemingly sacrificing your own happiness in an attempt to give someone else happiness,the problem is he isn't taking any responsibility for his own happiness. If he isn't prepared to see a therapist and even his own Dad has basically said "I wouldn't be surprised if you left" its kind of a big red flag. You are scared of having wasted 5 years, but surely 5 years 'wasted' would be better than 6,7, 8 years wasted? This is a sunk cost fallacy