Cat with FIC how to deal with the anxiety

My cat blocked twice, one from crystals in his bladder and the other was from inflammation two weeks after the first blockage. I don't know how to deal with the anxiety of making sure hes okay.

Now, he tends to go every 12 hours like clockwork but he does occasionally hold it up to 18 to 20 hours especially when I work. I am filled with anxiety because I worry when I get home I'll find him struggling. His vet said every 24 hours one pee is fine as long as he doesnt struggle.

He is on hills C/D dry because he refuses wet food all together (I tried everything I could think of to get him to eat wet food but didn't work), he gets a pouch of hydracare and has three fountains.

It's my first day going back to work so I am gone and cant monitor him besides the camera over the litter box and I struggle with counting the hours between pees. How do you deal with the fear they will block again? The last time he blocked he only tried to pee once and then just laid near the box and didn't try again so I worry I will miss something.