Sometimes their grief is being fed by yours. Work on giving him a lot more attention, exercise, learning new tricks. Basically, really truly tire him out the night before and the morning prior to leaving. If possible, try to arrange so that your and/or your partner can run home for a quick lunch/play time. Get the 2 way communications devices so you can see each other and talk to him.
I understand the costs. I had to wait after my beloved Sayblee died to get another basenji. So much expense trying to save her that it simply wasn't responsible to take on a new dog yet. A blanket or something with the smells... or wrap a new blanket around some of Jimmy's toys so that it gets the smell. Leaving that in the crate may help.
I am sorry for your loss, made doubly hard by poor Max's grief. He most certainly can feel you are grieving, but playing UP, higher happy tone, and more attention should help.