Something like this should be able to run any modern game at 1080p, though some with the settings turned down a fair way.
Case
PCS ENIGMA 6003B BLACK CASE Processor (CPU)
Intel® Pentium® Dual-Core G4600 (3.60GHz, 3MB Cache) + HD Graphics Motherboard
ASUS® H110M-R: Micro-ATX, DDR4, LGA1151, USB 3.0, SATA 6GBs Memory (RAM)
8GB Corsair VENGEANCE DDR4 2133MHz (2 x 4GB) Graphics Card
2GB NVIDIA GEFORCE GTX 1050 - DVI, HDMI, DP 1[SUP]st[/SUP] Hard Disk
1TB SATA-III 3.5" HDD, 6GB/s, 7200RPM, 32MB CACHE DVD/BLU-RAY Drive
NOT REQUIRED Power Supply
CORSAIR 350W VS SERIES™ VS-350 POWER SUPPLY Power Cable
1 x 1 Metre UK Power Cable (Kettle Lead) Processor Cooling
INTEL STANDARD CPU COOLER Thermal Paste
STANDARD THERMAL PASTE FOR SUFFICIENT COOLING Sound Card
ONBOARD 6 CHANNEL (5.1) HIGH DEF AUDIO (AS STANDARD) Wireless/Wired Networking
10/100/1000 GIGABIT LAN PORT (Wi-Fi NOT INCLUDED) USB Options
MIN. 2 x USB 3.0 & 2 x USB 2.0 PORTS @ BACK PANEL + MIN. 2 FRONT PORTS Operating System
Genuine Windows 10 Home 64 Bit - inc DVD & Single Licence Operating System Language
United Kingdom - English Language Office Software
FREE 30 Day Trial of Microsoft® Office® 365 Anti-Virus
BullGuard™ Internet Security - Free 90 Day License inc. Gamer Mode Browser
Microsoft® Edge (Windows 10 Only) Warranty
3 Year Standard Warranty (1 Month Collect & Return, 1 Year Parts, 3 Year Labour) Delivery
STANDARD INSURED DELIVERY TO UK MAINLAND (MON-FRI) Build Time
Standard Build - Approximately 8 to 10 working days Quantity
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However I'd suggest your friend considers saving up for something around £650 - like the above, but with a GTX 1060 3gb, a case like an Inwin GT1, and a 450W PSU.
The better case and PSU will open up more upgrade options in the future, saving £ in the long run. Why spend, say, £35 of the build on a 350W PSU when you'll only want to replace it with a 450W one for £50 anyway in 2 years time? Easier and cheaper overall to just buy the 450W one outright.
A GTX 1060 will last them a good while longer and give a better gaming experience upfront.