Ignore the software part actually, I'll just say he has £1200 and find cheap copies of the programs he needs. Ideally he wants to build asap, but if there's a worthwhile benefit in waiting I'm sure I can convince him.
In general my fps in tf2 is pretty good, pretty sure I'm not below refresh rate in 6v6 but I can check. I'm using the medium settings on mastercomfig atm and it's perfectly playable.
It's more outside of the game that I'm finding it maxing out, mainly watching 1080p60fps videos on youtube or highbitrate streams on twitch, to the point where I can't really do much else on the PC. I've got it clocked at 4.5ghz atm but I'm having to increase the voltage to keep it steady and it's only getting hotter as time goes on, so I figure if I upgrade before it dies I can keep it in an old rig.
Regarding overclocking, it's not a necessity but I like having the option. I'm also easy regarding AMD vs Intel. I've really fallen off keeping track of new CPUs that they have both brought out over the years and have no real idea of who is better to go with in certain situations nowadays.
I will be doing more video editing in the future too, mostly TF2 stuff but possibly other videos for youtube, which would factor into which CPU to go with.