His char starts with quite weak stats for a solo. 4 less positive attribute points than possible, very high negative attributes and only 33 astral points at the start. You can create a better mage without much effort.
For soloing through the trilogy I guess ice elf is easiest class. Spellcasting classes get more lifepoints at level up and elves can use more damaging weapons and better armor than the other spellcasting classes. Ice elves get 5 extra LP and 1 extra MR compared to the other elves.
If you want to try without spells dwarves are most powerful.
For getting perfect stats roll until you can boost all positive attributes to 13, then switch classes until you get Praios as deity for a free extra courage point. (If you choose mage try to get 38 AP also.)
If you play a mage, you'll only use your staff, else the magical axe you can find in Daspota is the best weapon. You might want to raise sword skill for using Grimring.
Strength is the most important stat, even for mages.
