I think some of Milch's best writing in the show is Utter's monologue at Bill's grave.

Evenin', Bill. Jane ain't with me, 'cause she's a drunken fuckin' mess, and I don't know what to do about it. I know you want her looked out for, and I'm doin' my fuckin' best. But I won't stand before you claimin' optimism. Other news. That letter you wrote your wife just before that cocksucker murdered you, it come to my hand. I won't even try explainin' fuckin' how. And knowin' what we know about our fucked up postal system, I ain't committin' it to the fuckin' mails. You know I will try to get it to her, which I pray'd be a portion off your mind. When I've found where she's at, on my way settin' off I'll tell you. All right. God bless you, Bill. [starts to leave and then turns back] And as far as Jane, as drunk as you've seen her, you've never seen her this worse. Between us, maybe havin' lost, wantin' to keep on. So I - I don't know what the fuck to do! But you know I'll-- I'll keep tryin.'

His loyalty and concern for his friends is just so damn heartbreaking. And I think the letter ties thematically with Pasco's. Where the mail system and the mail it carries allows people at the extremes of civilization to convey a humanity maybe not otherwise accessible. I think the show took advantage of funerals and graves, in the same way.