No system worked better for me than hledger - a doubly entry accounting tool for text files. It is super extensible, privacy focused and will be usable in 20 years still. No other tool has helped me stay on top of my finances as well as this, and I have tried them all. This is very subjective of course, but you might want to give it a try.
People get annoyed when they are weak. In this case, the weakness is that he has not reason he can publicly say, so he gets angry. What a loser.