@NitoTanaka
Why even care about some 12 years old kid who insulted you online in a video game, let alone fighting an online battle to "bring them to justice". I mean, I assume that you are an adult since you are married. Just laugh at him and move on with your life. Who knows; maybe he also go a warning or even got banned. Still, if you repeated whatever he said back to him, then you are not better then him. As adults, I think we all can agree that "he started it"-argument is just childish. Imagine if this was IRL. Would you, as an adult, jump in to the sandbox and start throwing sand and scream and cry only because some kid says something mean to you?
I am not neither defending or encouraging flaming but IMO, competitive gaming is a sport and too some degree, I believe that trash talking/insults/harsh words arent that of a big deal. Also, as a solo Qer I know how frustrating it can be to play with premade duos. You say you died and your wife went for the banner retrieval and respawn while your random teammate died and then he started to flame? Well, I cant ofc know exactly what happened but Ive played enough solo Q games to know that premade duos have a tendency to make prioritization in the game that they ONLY would do when it benefits the premade duo but never if it would benefit the solo Q and THAT can be very frustrating and triggering. So for all I know, your wife used him fighting 1v3 as a distraction to get your banner and then just ran off to respawn you while he died 1v3. Once again, I am not saying I know this happened but this is a very common scenario for solo Qs. So even if it isnt "right" of him to flame, its very likely that your premade duo-behavior provoked him.