You would need to ask the firm how they handle these matters. I am not a lawyer, but from what I have read, biological samples are pretty much the property of the holder, unless a state has a statute to the contrary.
You would want to test at the firm that has the largest surname project for him, since Y-DNA is only useful for genealogical research when compared to others. What is his surname? FTDNA has the most projects, but there are some big ones at Ancestry. You can search for the projects at both sites.
There are often sales around Thanksgiving, Christmas, DNA Day and the beginning of summer. This is an example. This sites seems to be a good one to get the alerts.