If he is use to, and likes Olympus jpeg output, that is where to start. There are several, to chose from, basic to very advanced. I have and do use other brands, but can't get completely away from Olympus. I don't think I will any time soon. Just upgrade. And used, 2nd and 3rd gen models are very attractive, in pricing.
And with that said, I am sure liking my Pentax K-01, after I found my preferred JPEG settings.