Adding to your ask about "excusing" Dean... Not to mention Dean is a very non-verbal person when it comes to his feelings. He's the most emotional and sensitive character on the show, but also the least verbal about his feelings. So he's grateful to Sam and Cas and you can see that. That's visible. Hopefully, one day, he'll be comfortable enough with his emotions to say it... but just because it's unspoken doesn't make it not true or not there. Words to live by.