Less than a week after former "19 Kids and Counting" star Josh Duggar entered a "long-term treatment center" following his infidelity admission, a member of his extended family is condemning his actions.

Jessa Duggar's husband, Ben Seewald, has not commented on Josh's cheating scandal, but Seewald's father has, in a new blog post titled "Grief, Shame, and Taking the Lord's Name in Vain."

"It distresses me to say that Josh Duggar's greatest sin is a byproduct of the sum total of his secretly sinful lifestyle. That is, that by his hypocrisy, he blasphemed the name of God," Michael Seewald wrote. "He claimed to be a Christian, but by his deeds he has suggested otherwise. With the name of God on his lips he lived a covert and extensive lifestyle of evil."

Michael also wrote that what's so hurtful "is that he was a loud voice endorsing Christian ethics and he has been shown to be a fraud." Ben's dad is "profoundly grieved" that Josh achieved such a platform and brought "only shame on God's holy name and the Christian faith."

Michael admits in the blog post that he, like many people, thought Josh had redeemed himself following the child molestation he committed as a teenager against his four sisters and a babysitter. He wrote that Josh "deceived us all" and "was a pretender."

Josh and Michael never developed a strong relationship, according to Ben's father, but he felt compelled to speak on behalf of those harmed by the eldest Duggar family son's actions.

"Though I have never gotten to know Josh very well, I have great respect for his sorrowing parents and immense sympathy for his dear wife Anna and their four children," he wrote. "I myself have been mourning over the irreparable damage that has been done to many by this whole circumstance, yet the reason I feel obliged to make these remarks is an overwhelming desire to vindicate the name of God."