I think that some of the Bible verses already quoted are appropriate for your boss. For example,
"Do not be afraid or discouraged, for the Lord will personally go ahead of you. He will be with you; he will neither fail you nor abandon you." (Deuteronomy 31:8)
And here's another:
"Work willingly at whatever you do, as though you were working for the Lord rather than for people. Remember that the Lord will give you an inheritance as your reward, and that the Master you are serving is Christ." (Colossians 3: 23, 24)
"May God go with you, give you strength equal to your task, bless you with success and grant you a safe return home."