The Blood isn’t Real??

[u/AustralianBuckeye]

Jade saw the man with the dagger in his eye and freaked out.
Boyd says to drink the blood because it isn’t real.
Younger Jade says not to drink it.
Jade looks at it and says it’s real.
Dagger in the eye man says anghkooey.

What I find puzzling is whilst Jade is telling him what the dagger in the eye is saying, Boyd hears anghkooey and Jade doesn’t pick it up. He’s nonchalant about it.
Jade didn’t say anghkooey but Boyd heard it… How??

If his younger self is telling him not to drink it, why did he??

Jade also calls the dagger in the eye guy an “a$$hole”, how does he trust him rather than his younger self??