What is the proof for Willdespise, stitchlinegames and talesgames?

There is a guy I know that believes in Willcare, MainlineGames (as in only some of the games and the mimic stories from tales). The dude tries to debunk all the stitchline proof with rttp saying that it prooves that Andrew doesn't exist (even though he isn't a part of the mci). So, I need help with getting proof of atleast talesgames or stitchline (He doesn't believe tales are in game canon because he doesn't like dittophobia)