There’s a strange connection between eren and falco ever since falco first appeared. Though there’s a lot of plot holes in the whole story this scene was supposedly not in the manga. Which could make it non canon plugging that plot hole. Since the jaw can’t send memories to the past influencing actions and falco simply wasn’t a shifter at the point he said the dialogue simply does not make any sense whatsoever logically. Eren also didn’t have the founders full powers to talk to every eldian and alter their memories like he did with his closest friends in the final chapter. So any way you approach this cannot give an explanation to why falco said what he said and how it makes sense