All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
In principle, a Muslim is innocent until proven otherwise, so it is not permissible to think evil of a Muslim without evidence. Allaah says (what means): {O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin.}[Quran 49:12]
It is even more recommended to think good of the Muslim if he is introduced by the Imaam of the Masjid as a witness. Moreover, the fact that he is a member of the Board of Trustees of the Masjid repels to a great extent the doubt that he does not pray.
Therefore, if the marriage contract took place in the presence of the guardian and two Muslim witnesses and they witnessed the marriage contract, then this marriage is valid and it leads to its effects. For more benefit, please refer to Fatwa 86384.
Hence, such doubt should be ignored and this married couple should continue their marital life and base it on affection and kindness.
Allaah Knows best.