He is using Aimbot.

21HS/49kill with MX4

http://battlelog.battlefield.com/bf4/ja/battlereport/show/1/951063988325677376/1117188778

25HS/52kill with M249

http://battlelog.battlefield.com/bf4/ja/battlereport/show/1/950974456915555648/1117188778

15HS/33kill with M249

http://battlelog.battlefield.com/bf4/ja/battlereport/show/1/950940120655165760/1117188778

17HS/35kill with G18

http://battlelog.battlefield.com/bf4/ja/battlereport/show/1/950733799095988992/1117188778

15HS/29kill with AEK-971

http://battlelog.battlefield.com/bf4/ja/battlereport/show/1/895982535055025024/1117188778

18HS/43kill with SCAR-H

http://battlelog.battlefield.com/bf4/ja/battlereport/show/1/888747227542994880/1117188778

https://www.bf4db.com/player/1117188778/snapshot/5912