I think my favourite is the third. I like the way Cas opens his hand and backs away, it really feels like ‘I won’t touch you if you don’t want’.
Or possibly the first, because or the way Cas looks at Dean. It doean’s matter what happens or what state Dean is in, Cas has nothing but love and respect and adoration for this man.
Or maybe the last because the way Cas touches Dean is so different from the others and it looks way less techincal, less angelic and… somehow even more affectionate if humanly or celestially possible. And Dean is so scared and in pain but he let’s Cas do it without hesitation.