Personally I think he should upgrade to 5800X3D when Ryzen 7000 comes out as I am sure it will be half the price since CPUs go down in price quickly when a new one comes out. That way he doesn't have to buy a new motherboard and new ram with it. And since a 5800X3D can trade blows with a 12900k and Ryzen 7000 should be around the 12900k performance... That's a lot of savings that can be spent on a beefier GPU or hookers.
Since we see how CPU heavy Ray Tracing can be, imo, you should do a complete platform upgrade only when the CPU is like 50-70% faster than the current one. And Ryzen 7000 is only supposed to be 15% faster than normal Zen 3 (not X3D). So even if it's 20% faster than normal Zen 3, it could very well be only 10% faster than 5800X3D in gaming for quite a lot of money.
Could be the difference between getting a 4070 or a 4080.
PC Specs: CPU: 7800X3D || GPU: Strix 4090 || RAM: 32GB DDR5 6000 || Main SSD: WD 2TB SN850
Essay Pro