Subreddits like cryptomoonshots could be the best way to grow, but they are flooded with bots spamming shitcoins and nobody reads it anymore. Where do you think he could advertise his project in a platform where people could listen
Unfortunately, Telegram have become mainly a place where bots create massive amounts of spam, and real projects have a hard time advertising.
I think a good idea to start with is to set up social media profiles, i.e. Twitter, Facebook, Instagram. Setting up a project group on Telegram is a good thing too. Then he can create his Announcement thread here on Bitcointalk and talk about his plans. If this is not just another project made just to raise money and disappear, I think there will be people in the Bitcointalk community who will be happy to help.