This is factually incorrect. Yes, the developer is in custody. No, TornadoCash is long gone. See mk4's
accurate answer:
The Tornado Cash smart contract is immutable and hence is still live on the Ethereum blockchain. I'm not sure about that IPFS site, but you can still use Tornado Cash today as long as you know how to manually interact with the smart contract.
Take note that Ethereum and "DeFi" is pretty much useless if a takedown of its front-end website literally kills the platform. The authorities can only take down the domain and the front-end; but the back-end will always be live.
As mk4 said, all you need to do is interact with the TornadoCash front-end in order to interact with it. Similarly, the project is open-source. Anyone can deploy the front-end and connect to the Tornado smart contract and they will have an exact replica of the original TornadoCash. The service is takedown-proof.