I am so sorry for your families' loss.
L123- I think if you re read your thread you will see you are terribly trying to control the situation. You need to let your H figure out how to live - even through losing his Mom - without drinking without you telling him what to do and who to call and then reminding him multiple times.
15 mo sober is one year and a quarter. He knows his tools work.
Tell him you love him, and that you are devastated about the suddenness of your MIL passing. but keep mum on all the reminders. Ask him if he wants you home regarding the trip, but if he says to go - then you go.
Have you ever helped a kid learn to bike? You know that moment when you let go and they wobble, start pedaling and you pray they don't forget how to steer or brake? He needs to figure it out - the steering and braking.
If he crashes, it is not on you.
Raised as a Codie, my sister and I several years ago whipped each other into a Codie frenzy by phone regarding my grandfather's impending death. It made me absolutely sick with anxiety (not grief). Then she got another call and he was dead. In the 15 minutes we flipped out over timing and family responsibilities and whatnot - he peacefully died. All of the flipping out was useless!! It was me just running the Codie track because under stress it was what I was raised to do. It is hard to get off that track because it makes us feel needed or something sort of sick.
Get off the track! You can light a candle and leave both your MIL and your H in your prayers. Peace,