Improve video streaming

No it won't. Streaming will be improved by adding more ram, replacing/upgrading your cpu and/or replacing/upgrading your wifi/network card. Since your laptop has a very weak cpu and it cannot be replaced there is not much you can do, though adding an extra 4 gb ram might help.
 


Unless all his RAM is currently being used up at 100% that won't help. I think the CPU should be able to decode 720p video just fine.
 


The laptop ships with only 4gb ram, so it will help overall performance.