Bad ping when gaming.

[#1]

Hello, I've got a few issues when it comes to gaming during the early hours of the morning.
During the day, my brother is always watching YouTube videos and thus I cant play online games (not enough download speed to support both at once). Because of this, I play at night/early hours of the morning. However, even then between 12 and 3am I get really bad latency, however the download is absolutely fine.
Here is a cmd prompt 'pinging' google (ping -t www.google.co.uk): http://imgur.com/MhwufCf
When I have good latency the 'time=x', x often hovers between 23-28. As you can see in the image this is not the case.
Here is a Speedtest performed at the same time: http://www.speedtest.net/my-result/4575346310
As shown in the image, my ping is still bad, but the download is fine.
I know that at this time my brother is not using the internet, hence why I choose to play games at this time. However this is preventing me from doing so even at these times.
Something else I've noticed, is that this only happens when my brother has used the internet/watched youtube videos during the day. For example last weekend I was home alone and the internet and my latency were fine the whole 48 hours.
I understand this may be a bit long-winded, but its really getting on my nerves.
Any help appreciated, thanks.

[#2]

When the issue is happening again.
Run a trace route as that will show more than the ping, even better would be if you knew the server address of the game but that is a long shot,  I wouldn't expect you to know that but if you did/could find out and ran a trace route on it then I'm sure it would show some answers.
If not do a traceroute to something generic like bbc.co.uk or plus.net,  could still well lead to some answers