In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
In responding to your question, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
The answer is a definite ‘no.’ You are not allowed to break your fast to share family Thanksgiving. I am referring to Ramadan fasting which is the fourth pillar of Islam. Hence, no Muslim who can fast should skip it.
However, if you are speaking of optional or voluntary fast, you are allowed to break it, and you may make it up later if you wish.
Allah ordains the believers to honor our parents – even if they are non-Muslims; and yet qualifies it by stating, “if they were to force to associate partners with Allah – do not obey them; however, deal with them excellently in all other worldly matters. Also, follow the path of those who are ever turning to Me in repentance.” (Luqman 31:11)
Almighty Allah knows best.