The system you describe sounds similar to the one I use in my own module, The Scroll.
After trying several approaches, I ended up using an On Perception from both creatures and PCs to run through various function that do things like:-
- Check a bestiary entry required.
- Check any scaling that may be rquired.
- Check monster info. (Naming convention with coloured emphasis. E.g. Puny, Wary, Normal, etc)
- Start ant TB Combat (if used).
When it comes to scaling, I also used a MAXIMUM possible with respect to some creature types and then also employed a + 1-3 levels (or scale to party level) approach subject to creature type. In fact, there is room for more scaling subject to what the creature is.
The system is TRUE level scaling as well. It is also balanced on things like:-
- Party size.
- Party level, especially low level considerations.
- Game difficulty settings.
- Creature actual physical scale if level scaled. (Some types only.)
My warning would be to players: Make sure NOT to use additional scaling alterations like this when playing my module (and other mods), which already employs such a balancing system. Personally, I would recommend you advertise this to builders as something to possibly use, rather than to players who may really mess something on a module if they are not careful.
I hope things turn out OK for your brother.