I'm not sure what your budget is but sounds like John Smedley might be a good option for tops. I can't post links properly atm but google & you'll find his tops. The material's are beautiful & they are a perfect combination of smart & casual. They cost a fair bit but last forever & look expensive.
Are you in London? Selfridges used to do a free style advice thing inc for men. They worked miracles for my sisters' dp who hates clothes & shopping.
For shirts he could try Pink's casual range but they seem to be a bit funny with their sizing to me. Again, pricey but they are very good quality.
I buy dp loads of shirts every time I go back to Italy. Masses cheaper than here, beautifully made & the fits offer such a range there is a shirt to suit every man.