The good thing about the Western is that you mostly look for the size to fit the butt, not butt + legs like in English. I go with 18" English + very forward CC (as my legs don't fit anywhere), but my Western saddle I sold this year was 15" and perfectly fit my butt. So really depends. English size - 2 is the rule, but it's not always true.
As for types, unless he's planning on doing something specific (like barrels or cutting) I'd go with just usual (pleasure/trail) saddle. You can also look into synthetic - cheaper and easy to care.
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