The insurance companies seem to look at two things - why someone is on coumadin and their access to a lab. If he has a mechanical valve, there is a great chance. If he is on coumadin for another reason, it might be tougher. However, the combination of being on coumadin and frequent traveling might work.
He should get the support of his cardio who must fill out paperwork on the reasons for a home monitor if going for insurance coverage. Have him emphasize the difficulty of getting to a lab for testing due to traveling and, if he will attest to it, the need for weekly testing.
If no insurance, the cost should be around $1500 from someplace like QAS (be sure and talk to them about not having insurance. I believe you can get monitors on ebay but not sure about manufacturer warranty or support. Test strips can be anywhere from $5 to $12 each, again depending on where they are purchased.
I am quoting INRatio pricing. Not sure about the Coagucheck XS. The two are very similar. I have the INRatio and love it.