Sorry, I disagree. I have been to the USA on business afew times, and my problems is keeping my blood sugar down. I suspect then that your boyfriend is a well controlled diabetic, who adjusted his insulin...and got it a bot wrong. For me, I would loosen up the control a little bit. I would never normally say, let yourself go a bit high, but for hs own safety, it might be teh best thing, for a few days only though!!
Practically thought. get him to tell the hotel that he demands a personal wake call every morning...not just the automatic one they do these days. They should do this if he explains why. Also, stay off the wine and spirits, as tehy canmake your blood sugar go low. If he is on business, then he can charge is calls back to his company, so he has no excuse not to phone you..lots!
This may eb one of those lessons learnt the hard way..but he should have learnt it, and his colleaugue will now be more on the ball too,
Please don't worry (easy to say I know!) Last night, it all went wrong, and he lost his phone, but he did get back to his room OK, he did wake up today and he was unharmed. Yes, he has to be careful, but I imagine he is feeling very silly now, and will not let it happen again!