HELP!?!?

i feel like if you've addressed it a couple of tiimes it maybe time for some sort of disciplinary action, like isolating them from the situation... like say next time you see it happening, say "thank you for helping but ive got it now" , and if they continue on the topic try sitting them in their room or a separate area for a little, call it timeout, and after that go talk with them and ask why they're doing it and re-iterate that you're the parent and they are the child, and if they feel like you need help have them ask instead of just doing- and that way you can correct unwanted behaviors before they start but i do think it all takes time.. i hope this helps- ive not been in this situation with my own mostly because i only have one and she's 10m old, but my father had dealt with it in my brother and sister, my brother ended just wanting to be helpful and setting boundaries helped