if he claims to be the only one that's indication that he's not aware of the hundred of time travelers, I have spoken with some REAL time travelers, you wouldn't belive it, basically there's 2 options on how they do, either they have created a time machine themselves or have "borrowed" one, they usually don't want unnecesary attention, are very humble and won't reveal anything, because that would interfere in your own development, imagine for example that you created a time machine in your 90's and came back to your younger self to teach yourself how to make one, if they interfer many subtle changes happen, thus your "history" would be altered