It's not as bad as it is for MBA, law, or (at the extreme) humanities PhD programs. In those fields, it's not even worth going if you can't get into a top program. Nonetheless, the ranking of the PhD program matters.
What matters more than the ranking of the program is the reputation of the advisor. However, at a no-name grad school, there may not be any reputable advisors in the field he wants to pursue.
It's not as bad as it is for MBA, law, or (at the extreme) humanities PhD programs. In those fields, it's not even worth going if you can't get into a top program. Nonetheless, the ranking of the PhD program matters.
What matters more than the ranking of the program is the reputation of the advisor. However, at a no-name grad school, there may not be any reputable advisors in the field he wants to pursue.