score:5
You are making a business trip to the UK and will stay in corporate housing, you want your husband and child to accompany you...
Can he mention that he will be staying with me at my office provided accommodation?
Yes, if he is staying in corporate housing provided by your employer, he should write it down.
Also, should he mention any accommodation costs?
If there are no accommodation costs that he will bear, then he should 0, otherwise he should report what he expects to pay.
What should he write in living expenses?
He should calculate the expenses that he will pay and put the result on his application.
Other notes