Ok, I've decided.

Diego will go stay with the vet.

The last time they tested the alarms they were done by 10 am. So he really will only be with the vet for 2 hours, maybe slightly longer, or shorter.

Figure this way he will be glad to get in my truck and glad to come home.

It seems like the lesser of all the evils. He might be stressed but I think it will be less damaging than staying in our apartment. Maybe he will even learn that being at the vets isn't so bad because nothing will happen to him this time. Maybe, just maybe he will make some new friends.

I will call Sabrina at the vets office tomorrow to make the arrangements.

Thanks everyone for your comments and for helping me come to a decision that I hope is in the best interests of my boy. Despite his faults I love my boy cat to bits!!