Possibly looking too deep into this but...
After rewatching Infinity War, I’m at least 75% sure Loki fakes his death and here’s why...
First of all, Loki knows more than anyone what Thanos is capable of and he just saw Thanos pulverize the Hulk. I don’t think he’s dumb enough to believe he can take out Thanos with his little dagger.
Second of all, I believe there’s some word-choice trickery at play during Loki’s exchange with Thanos.
First, Loki glances at Thor when he calls himself “Odinson.” A little hint to Thor that a) he’s still on his brother’s side and b) that Thor might want to pay attention.
He then declares his “undying fidelity.” Thanos replies that he should have chosen his words better. But the thing is, I think his word choice was very deliberate.
I don’t think I have to explain what “undying” means but fidelity (as I saw another post point out but I can’t find at the moment. If anyone else has seen it, please reboot with a link do they get proper credit) means this:
So basically what Loki’s trying to say is “I’m not dead, it’s just a copy.”
Now, we know Thor is a pretty smart guy. He’s knowledgeable about science, strategy, how to speak Groot, ect. But I don’t think he’s a wordsmith, so Loki’s coded message didnt get through. Plus, he was under a lot of stress at the time what with Asguard being destroyed and all.
Granted, I could be looking too deep into this. I could be completely wrong and Loki’s really dead after all. But if he’s alive, I really want them to reunite with a brotherly argument about how Loki let Thor think he was dead. Such as:
Thor: *Hugs then punches Loki*
Loki: Ow, what was that for?
Thor: You let me think you were dead, you jerk!
Loki: No I didn’t! Didn’t you get my message?
Thor: You never sent a message!
Loki: Yes I did! I said “undying fidelity.”
Thor: You were your fake-pledging loyalty to Thanos!
Loki: Fidelity can mean “loyalty” or an “exact copy.”
Thor: Well, exuse me! All the dictionaries blew up when Thanos attacked our ship!
Loki: Well, when we’re finished defeating that big, purple cretin, I’ll get you a new one!
Thor: *tears up and hugs Loki again* I did miss you brother.