SHA 256 is not susceptible to quantum attacks but ECDSA is.
If you are responding to our interaction just above your post, then read carefully what the user wrote.
We know SHA-256 and ECDSA won’t be safe forever. And no, that’s not FUD, it’s projection grounded in science, not faith.
He does not explicitly state that SHA-256 is susceptible to quantum attacks, and this part of his post is very accurately written. They won't be safe forever irrespective of the topic of quantum computers. They will be broken in one way or another, eventually.
SHA 256 will be safe forever but ECDSA will be broken by quantum. Bitcoin can adopt a replacement for ECDSA but satoshi's old BTC will still be vulnerable. natasha otomoski's haircomb uses SHA256 to fix the ECDSA issue.