Why not send a cryptic email to your grand son to come and see you and help you. Anyway his universe won't be affected. Lets assume everyone sends email to his future grand son or great great grandson to come and visit you. He might be there tomorrow if there is a time travel possible in 100 years.
if no one shows if billion people send email to their grand grand...son , And no one shows up (out of billion travllers) out then either john titor is a fraud Time traveller and john titor will be a fantasy writer and entertained us well.
So first all billion people have to believe in Time travel and ask your future grandsons to come and meet you. If you don't believe there is no way time travellers going to come in your present.
if no one shows if billion people send email to their grand grand...son , And no one shows up (out of billion travllers) out then either john titor is a fraud Time traveller and john titor will be a fantasy writer and entertained us well.
So first all billion people have to believe in Time travel and ask your future grandsons to come and meet you. If you don't believe there is no way time travellers going to come in your present.