High Ping while someone else is using internet

[madaxas]

as the title says, sometimes im getting 500-1000ping when my sister is using internet on her phone, propably watching netflix or facebook idk, i play lol very often and im getting these high pings but the best thing is that when im playing and watching video on youtube in hd my ping is like 120 max but when someone else is using internet ping jump to 1k.. idk what to do i already changed channel to least crowded. My internet specs: 7mb dl 1mb upl

 

[Petrossa]

Simply put, you need more!
Streaming alone will consume most of that 7mbps you have, leaving little left for gaming.
You could try prioritising your gaming traffic through the router, if the device allows you to set these kind of settings.