I did a clone of him using the 6 custom adventure option in Single Player mode, and this is what will happen for his combat prowress had he been recruitable via legit means,
Every stats about him remain the same and they are based on recruiting him at Beregrost right from level 1 (Hence Grandmaster in his Axe proficiency). No cheating is used.
For Sure he is pretty godly even before I could reach chapter 10 (At Boareskyr), not to mention he isnt getting the best items for fighter (such as Helm + Cloak of Balduran) since that belong to my Charname -GM Dual-Wielding Scimitar Half-Orc Fighter.
I had Coran too and He is also pretty good although nothing too spectacular, yet! (Haven complete yet)
Str: 19 (Big Fisted Belt)
Dex: 18 (Gauntlet of Dex)
Con: 19 (Claw of Kazagoth + Tome of Constitution)
Fighter (Level 9)
Again, no cheating used. His saving throw are about 0-3, literally demi-godlike.