I'd go for all natural fabrics if I could find and afford them, and if they worked. I have to take into account the use the articles will get (VERY rough, in the case of such things as rugby shirts and school trousers!), the cost when the lad is still growing, and their purpose. A waterproof jacket for cold wet weather (think wearing in it horizontal driving sleet waiting for a school bus! Or walking the fells...) needs to be fully wind and waterproof, while also being light weight, warm (or large enough to go over the blazer or orhter warm layers), and cheap enough to replace at least once a year when he grows out of it (he's already 6'1", with a 42" chest and 17" collar shirt, and only 15). And then it has to pack down into his school bag during the day... I've yet to find a natural fiber garment that hits all those requirements.
On a recent (September) trip to Dortmund I didn't notice any more natural fiber garments or fabrics for sale or in use than here in the UK. The friend I was staying with was impressed with our local recycling arrangements: better than Dortmund's when we compared them for what was recycled and the collection arrangements.
Things may have changed in the last 10 years, but one of the best coats the GMNT had was bought in Zurich (we'd gone for lunch and he'd forgotten his coat! Long story...
). It was a three-layer Gortex type construction in rip-stop nylon, from one of the better kid's clothing shops. That coat looked good, did him two years (they bought it with room for growth), and I saw it on at least 3 other kids after he grew out of it. It still looked new.
The point is that there are times and places and conditions where both natural and man-made coated fabrics have their place. What I try to do is pass on to friends and/or charity shops anything that we no longer need or fit into, buy or inherit things on a similar basis, and make sure that everything that is still wearable gets used to the max, no matter what it's made from. I cannot pass on shirts with permanent stains, trousers with patches, and blazers with the collars ripped off or sleeves hanging out. And I can't find pre-loved clothing in his size! But we have used old trouser legs for stuff bags, made things like the GMNT's Hussif out of remnants from other projects, and I recycle as much of any toile as I can into peg bag linings and toiles for smaller garment parts. I've spent my whole life doing this, as my mother has before me. 'Make do and mend' didn't stop here with the end of clothing coupons! The modern throw-away society has largely passed us by (even my laptop computer is old and pre-owned).
The lads at the GMNT's school (and now many others here in the UK) wear suits for their final two years. At that time they need a suit for things like university and job interviews, so wearing them to school makes sense. The boys tend to look and behave like responsible young men rather than school kids, and take pride in their appearance (when in uniform they do their utmost to 'customize' it to the latest uniform-wrecking fashion!). Outfitters like Burtons do package deals of shirt, tie, suit and shoes for under £150. It looks fine, the lads are still growing, so parents are reluctant to spend excessively, and the items are easy care, so don't distract them from their studies by taking extra time to look after. Poly/viscose mixes with Teflon coatings are ideal for the use, while not as tailorable as a beautiful wool at many times the price.
By the time he needs such a thing, my son looks like being about the size and shape of Jonah Lomu. If no-one makes suits of this type for someone that size in a version we can afford, I may well be making it for him. This is one of the reasons I'm here to learn and to extend and improve my skills. If I can make him a decent suit from something Teflon coated and poly/viscose or a wool mix for a price we can afford, then I shall be happy. I certainly won't be sending him to school in a pure wool suit that cost me £35 per meter or more for the cloth! A GOOD suit will come later...
A good book will fall apart in your hands... A good suit will be remade for your grandson.