WOW, I would not stop because it shows that you care but you might think of a way to do it that is not a challenge to him. Such as ” I hope to go to bed by…, you know I worry about you and can’t really sleep until you are home, could you please call me at “x” time, so I can hear your voice and know your ok?”. Of course that doesn’t apply to Shabbos. You can also have the discussion about sharing your key. Sharing your key would also make you a “team” in a sense, at least in this issue.
There is another challenge this week which might surprise you. Do you think he will participate or ignore Tisha b’av?