If the conventional method doesn’t work, you might try a different method (ex. bunny ears).
Sometimes kids can be resistant to parents showing them something. If that’s the case, you might want to set aside a sizable chunk of time, do a Youtube search for tying shoelaces, and turn him loose. (There are many, many videos on Youtube). Tell him that when he masters thing his shoes, according to whatever standard you set (X times in a row, X times in a given time interval, etc.) you’ll celebrate with reward (treat, game, TV for the rest of the day, etc.).
https://m.youtube.com/results?sp=mAEA&search_query=tying+shoes
Do you think he might be more receptive if it wasn’t another shoe-tying lesson? Maybe you could recruit him to help you wrap gifts and tie bows with ribbons on them. If you payed him per gift, he’d be extra-motivated, and you’d get the gifts wrapped. Alternatively, he could tie bows on anything, just make up a project..
Don’t forget to teach him about a double knot to help KEEP his shoes tied. It should be a cinch after he learns to tie them in the first place.
Good luck to you both.