Outside of the newbie areas it's common to see much harder mobs wandering amongst lower-level ones. You'll get used to avoiding them. Time to start exploring! Maybe switch it up and move to Steamfont and you can be the one buying spells for him instead? Also note that there's a caster guild in Freeport where you should be able to buy your spells, and there's even an underground necro/rogue one too!
https://wiki.project1999.com/Per-Level_Hunting_Guide <- this has many great suggestions (spoilers!)
Don't forget to /consider everything! Lots of things want to kill you...
-Mcoy