He could have gone lower today. And that 45 earns him a dose reduction. I would reduce his dose to 1.75 starting tonight...if his BGs come up high enough to shoot a dose tonight.
I'm going to go to bed, so will not be up when you test at your regular shot time to determine if it's safe to give his insulin. If you need help, just ask, and if you are not getting any responses when you need them, then post over in the Lantus Tight Regulation forum, there is almost always someone logged on there, and the folks know your Lantus.
Do you have plenty of test strips, and high carb food or syrup, just in case you need them? If not, you might want to stock up, BGs numbers depending if you can run out or have someone else run out for you.
Have a good night.