Have you read the last few issues?

Its just the President. Its not like they killed the entire line of succession.

I wonder what consequences, if any, that Katherine Johnson hearing the words "time machine" and "Rittenhouse" will have? I wonder if this show will ever get to the point where they need to show that they are in fact from the future?

Well we've seen that being a time traveler insulates you from changes in the timeline, so Flynn wouldn't be personally affected by the change of now having an older brother.