How can the two girls be convinced to fear Allah, the Almighty, especially since they pray in my presence but lie about their prayer when I am absent?

Raising daughters is a great virtue, for they will be a shield from the Hellfire, and whoever takes care of two daughters until they reach maturity will come on the Day of Judgment, he and the Prophet, peace and blessings be upon him, like these two [holding two fingers together].

To address the daughters' lack of fear of Allah, you should frequently mention Allah and His names and attributes in front of them, explain our need for Him and His self-sufficiency from us, and mention the Hereafter and scenes of the Day of Judgment as depicted in the Qur'an. Also, make use of a concise commentary of Juz' 'Amma, such as "Tayseer al-Kareem al-Rahman" by Ibn Sa'di or Tafseer Ibn Katheer.

Likewise, there should be sessions dedicated to the biography of the Messenger of Allah, peace and blessings be upon him, and his Companions, and utilize Islamic audio recordings that soften hearts, explain the ruling on abandoning prayer, and warn against lying.

You should frequently supplicate for their guidance and steadfastness, be patient with them, show compassion and fear for their destiny, avoid shouting and quarreling, and reward them when they do good.