I'm sympathetic to his views, but I don't think killing 10 (15, or 20, or however many) is going to bring about the result he wants. It will foster more anti-white resentment and attacks against them, in a time where we are already seeing record levels of this. The best thing you can do if you feel like this guy about white replacement, is to becoming the best, most educated/skilled/rich/whatever version of yourself you can be, and have kids. Very straightforward goals, with countless approaches to going about it.
I firmly believe that the lack of positive and socially acceptable avenues for expressing white identity are heavily contributing to these attacks. Everywhere you look, people will talk the most abhorent shit about white people that you wouldn't dare say about any other group, and this is considered normal and acceptable. So you can't have any pride in your heritage the way other groups can, and you are supposed to sit and take all the shit thrown at you without budging an inch. It's a breeding ground for these situations.