GRAB HIM
honestly it's kill or be killed for both characters, and falcon is so fast, you need to be unpredictable in general. Teleport is decent but can be punished if predicted, so
it sucks
I mean, you have to play reactive to the falcon. if he is aggressive you might be able to catch him in nairs
if he is more conservative, you can start attempting to use shadowballs
get dat grab, make it count
edgeguarding and grabbing and techchasing are all super key in this MU for your offense, but I'm sure your problem is defense, so lol, i mean
you have a few options, they all kinda suck and are punishable. my favorite is RANDOM USMASH, but it rarely works.
eh
roll left, roll right, spotdodge (nottttt recommended), sh nair, sh shadowball charge can catch people sometimes if you are facing away, CC grabs at low percent can at times work but a lot of things will push you away too much, wavedashing away from some of his stuff can work just like w/ any character but watch out for nair since that thing has massive range, teleport can be used like rolls but in the air