1) $2000 seems really excessive just to play online darts. Are there OTHER TASKS or GAMES he would use it for?
2) Could you specify SCREEN SIZE at least?
- 15.6" is lighter, more transportable
- 17" is heavier but a larger screen (recommend 1600x900 or 1920x1080 resolution)
3) VIDEO STREAMING:
- the ROUTER is also a factor
- your NETWORK BANDWIDTH is also a factor (especially your UPLOAD SPEED)
- the DISTANCE between laptop and router is also a factor
*Probably any laptop is fine for wi-fi connectivity bandwidth, but you can BUY a USB adapter if you need better.
Feel free to ask any questions but I didn't give a specific laptop as I thought you should understand this first.