I would say this system is safe until one password - through no fault of their own - gets leaked. Worse even, two of them. If a bored hacker sees them in a stolen list, they could go to town on all other accounts. So you should advise your acquaintance to change their system. Long passwords are great but if they repeat a lot of characters they are immediately less useful. If the repeating string is known it makes brute-forcing other accounts that much easier.

The best advice is to keep unique passwords for all accounts. And by unique I mean not following a system like that. Long, random, non-sensical crap is best (but also most annoying) - for now. Once quantum computers become a thing, all this probably won’t matter any more.