Notice the reference to Chuck (thermal blanket)???

Really liked this little detail. At first, Jimmy refuses to use Mike’s spare thermal blanket? Why? Cause he enjoys freezing his balls off? No. It’s probably because it painfully reminds him of his brother Chuck, who would wrap himself with these very same blankets to shield himself from electromagnetic fields.

Then later, Jimmy wraps himself in the thermal blanket and walks around in a daze, just like his brother used to do. He basically wraps himself up in his brother. His brother is like a protective armor because Chuck is Jimmy’s reason, his “why”. Mike told Jimmy that what keeps him (Mike) going is his people, for whom he wants to leave something behind, essentially suggesting that Jimmy do the same (presumably thinking Jimmy would do it for his wife). But Jimmy does what he does for his brother Chuck, who left HIM behind. He does what he does at this point, in part to prove himself to a ghost, in part to defy that very same ghost’s lingering judgment, in part as a futile attempt prove to himself that he is no longer bound by Chuck.
But Chuck will always be with Jimmy. Regardless of Jimmy’s choice of name, his wardrobe, his actions, Jimmy will always have his brother factor in to his decisions. Hence the symbolism of the thermal blanket.

My take, at any rate.

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