What would a young man wear to an informal wedding reception- not a suit

[DelphiniumBlue]

We've got a family wedding celebration coming up- the wedding has already happened but this is the delayed celebration. It's an evening do, and DS has been working from home for the whole of Covid. He has no sense of style, lives in the same jeans and tshirts all the time, has nothing remotely suitable to wear. He doesn't care about clothes, but has said he will put on something new, if I help him source it.
I don't want to be embarrassed in front of family with DS looking like a
tramp -computer nerd- and don't mind helping.
But I don't know where to start for smart casual/presentable Any ideas?
He is 6', heavily built. Any suggestions welcome.

Sorry about my linkfail, can't get it to work and as the dress is a few years old can't find a better link!
But it covers all of ElephantofRisks criteria- it's a red leopard print Mint Velvet dress, semi elastics red under the bust, loose/ish round the middle and just covering the knees/ it even looks nice we it's flat sandals. I tried it on last night and it fits so I'm good to go!
I've ordered some things for DS , and pleasingly he is very grateful! Hopefully something will fit -and look nice .
I've also got to sort DS2 but he is younger and a bit less bulky and I can usually clothe him from H&M. Fortunately DH can dress himself!

That sounds fab all round OP. I hope you all have a lovely time and rock your new looks

If it helps, DS2 tried about 10 different suits on for a wedding we were going to and looked terrible in them all, but he then went for a different look completely and looked brilliant. So don't despair if the first outfits don't work out, maybe push him out his comfort zone and try again.

So I'd advise looser cut jeans or trousers will look miles better than skinny..they're not in right now anyway..get a really good raw selvedge Japanese denim from EV or
Bruine or Boss. Generous width over thighs, long and dark dyed..black or indigo/black. Not flared..straight cut.
They are as well cut as top end suit trousers.
Then sparkling white linen shirt ..nehro collar, worn open to be tucked in at front so tail shows, chunky watch..not digital..vintage with hands..v cheap on ebay..brown, worn leather strap and a dark navy pin stripe suit jacket...long cut..coloured lining..Paul Smith..lots of bargains on eBay.
Shoes..Black, almond shaped or blunted toed Chelsea boots. Leather
Socks underneath to be one of the bright colours from the lining.

Jeans, but not skinny.

Nice shirt.

Blazer.

Good shoes!

(Just as a suggestion for overall outfit - have seen that you’ve ordered some stuff so hopefully it’ll all be just right!)

I would get him a white casual/smart shirt, navy chinos and some smart trainers or boots from Next. Very reasonably priced. You can order it all online and decent quality.

Update: DS1 has ordered a made to measure linen jacket which he will probably wear with chinos. But his whole wardrobe has now been updated with a couple of linen shirts and a heavy twill jacket, so he's happy.
I now have to find something for younger DS ( which I will have to pay for so H&M or similar) . Can't be too similar to what DS1 is wearing! Any links would be fab!