In the end, perseverance seems to be the key here. He's not putting an incredible amount of money down every month, but still he has managed to obtain a lot of Bitcoin, 4.47 BTC from his last update.
Have you tried something similar?, maybe now thinking about doing it?, I think it's a great idea.
He did invest in an opportune moment, that does make it better for him. He does buy bitcoin a lot and considering 500 euro every month, I think it's cool that his 500 euro a month buys different amounts of bitcoin all the time when the price falls, and his fiat stack does increase anyway. He started at the bear market of 2018, which means he bought cheap, and then when bull run of 2021 happened he got super rich, and even though it did fall, it never went that low, so it looks like he is going to make even more soon enough.
This is the method I use, similar method, but the difference is that I had to cash out multiple times since he started for personal reasons, thankfully I have just 2k debt now, could have been 20k debt if I didn't invest into bitcoin.