What did he have as medical insurance coverage? Did he change plans starting in July?

If you are only partially covered in the year by a High Deductible Health Plan that qualifies for HSA, you would pro-rate your HSA contribution by that portion.

Example:

He had 1/2 year eligibility and the other half, was he in a plan that still qualified?

For example, there is at least one Medicare Supplemental plan that is HDHP and it is not qualified for HSA.