I see a bitcoin address which someone says is a dust address but unable to prove if it's actually a dust address.
How will we know if you or someone else doesn't hold the private key to this address. What if you have the private key to this address and someday you decide to spend all the coins in this address.
It is a
dust address, not a
burn address. I think that you've made a confusion.
If it would have been a burn address, your question would have been valid. For a dust address, it's expected that he does have the private key for it.