Little back story, we both work for a small data company and we are both data analysts.
He was moved over to this new team about 4 months ago doing something brand new for a new client we had acquired. The work they gave him was stuff most analysts won't touch until their second year of employment. His new lead confirmed this for him and said he should be fine. Few weeks in and he hates it because his lead is condescending and rude when they talk in person or over teams (I read some of the messages and she came off very rude). During this time, he created procedures on something he'd never done before (out of his scope) and when he did the work he got some quality check feedback saying he is messing up a bit but the mistakes aren't grave, its just a couple of typos and converting things wrong but can be fixed very quickly.
Fast forward to June, he is being helped by his lead to become a better analyst at this new task and he is doing well and no issues on his quality checks. He advances a bit more and just has a few issues again with just some typos nothing too major. He creates a tool that will clean up the data for him and all he has to do is paste it where it needs to go. Tool works flawlessly and he is being praised for making the tool (outside his job scope). So his lead has been 3 months behind on checking his quality to make sure everything is ok, but still tells him to continue with his work. The tool he created pushed them 3 months ahead of delivery schedule.
He is called into the managers office yesterday and is being told that he is being let go due to performance, his last 3 months of work hasn't been passing quality checks. He had no warning, no written performance plan, nothing that would indicate that he is in jeopardy of losing his job. The only comment that was made by his lead was that she would still have to look over his work because he isn't quite there yet but will be there soon. The issue is that they are only looking at stuff he did his first month, they haven't looked at anything new, he has made multiple updates and revisions to his work. The person that was checking his work even told him that he was using one of his old files that hadn't been updated since mid to end of June. So he was pissed off because if there was an issue with his work, why would you let him continue to work on something he wasn't good at, but get 3 months ahead of schedule without taking the time and making sure everything is working well.