Yeah, I loved this scene, well, I absolutely love this whole episode tbh, it’s one of my favourites.
*checks wikipedia* OMG ITS AN ANDREW DABB EPISODE *flails even more* I love this man, I really do, I need to send him a fruit basket for every time I realise he is behind a part of this show that I love, which seems to be about an 80% hit rate at the moment.
Cas is extremely depressed, BUT he has enough of a hold of himself to know what his trigger might be (Heaven) and what will help him (working, living, hunting with Sam and Dean).
So, talking Faith:
Isn’t it ironic, that Cas had so much faith in his Father, in God in seasons 4/5, that here in s8 he is struggling with this, and we know that by 11x23 he has completely transferred his Faith from God to Dean. I’ll never not love how he completely sidelines Chuck and goes straight to ask Dean what they should do, that he ignores Chuck in the bar and his only words when GOD AND THE WORLD IS SAVED are “and Dean?”.
Meanwhile Dean goes from having no Faith in God pre-Castiel to in s8 praying to Cas every night, then by 11x23 Chuck has made him pancakes and watched all his porn and accepted Cas as family and by s12 it’s clear there is more to it. He also discovers that he is LITERALLY made in God’s image with all the parallels, he even SAVES GOD and reconciles him with his sister, although he doesn’t idolise Chuck at all.
I mean, its beautiful how they come to kind of meet in the middle and the timeline is fantastically intertwined?
Meanwhile Sam as you say does seem to “endlessly chase the divine” albeit with some ups and downs, but he later also evolves to have (as much?) Faith in both Dean and Cas too whilst at the same time he is the one to care for Chuck in the bar for example.
And now? Their Faith in each other is metaphorically hanging in the balance. Dean knows Sam has been lying, he is about to discover that Cas is on Earth and not dead and hasn’t been answering his calls. Sam and Cas’s Faith in God is about to get tested again with the Lucifer/nephilim story and this also is going to test them on a moral standpoint.
Faith and Free Will are so core to this show and this scene shows just that, Cas’s Faith in the boys ability to help him and his choice that being with Sam and Dean is what will help him get through his difficult time as he himself stops “endlessly chasing the divine” and stays grounded with them for his sanity.