That's possible If he has high quality videos. Otherwise that strategy cannot work.
There's a guy named Youtube1978 who posts frequently on here and is known for his anti-promotion stance. I used to be 100% against it but I've softened on that a bit. I still think there are ways to promote that will result in high retention views (specifically targeted YT search result advertising, for example), but after taking careful note of my retention from various traffic sources across all of my channels I've come to the conclusion that almost any promotion that intends to drive viewers from sources outside of Youtube will hurt your channel (the exception being Reddit, but only if your content has very broad appeal and is very compelling.
The reason I brought him up is that he said he has channels similar to yours and says he has had great success in not promoting them and just waiting it out. The theory is that the few views that trickle in over the course of a few months will be high retention views and will lead to your video ranking highly with the suggested video algorithm. Again, that's just his opinion but I mention it because he has top ten type channels as well.
Good luck.