Report Twitch Deleted Stream?

I have reported a streamer or a video of him which he then uploaded to Twitch, where he had passed on personal data.

I reported this stream, but he just deleted it and he wrote it in his instastory.

Can Twitch still track his stream or does something happen now if he has already deleted the stream?

They should be able to track it but nobody can tell you exactly only one employee

Yes, it is possible that nothing is ever deleted. Remember that it is always saved on the servers for a few hours!