How can a Muslim repel the whispers of Satan when feeling religiously superior to their family?

Praise be to Allah for guiding you to acts of obedience, and we ask Him to keep you steadfast and protect you from self-admiration.

We fear that your feeling of praying and fasting more than your family might be self-admiration, and a Muslim is commanded to compare himself to those who are higher than him in religious devotion to realize his shortcomings. For Allah might accept a small amount of worship from your family, and perhaps they have hidden good deeds.

Do not guarantee the acceptance of your deeds, for no matter what a Muslim does, he remains apprehensive, questioning his deeds and fearing non-acceptance, as confirmed by the Almighty's saying: "And those who give what they give while their hearts are trembling that they will return to their Lord – those are the ones who hasten to good deeds, and they are foremost in them."

'Aishah (may Allah be pleased with her) explained the verse by saying that they are "those who fast, pray, and give charity, while fearing that it will not be accepted from them." So, apprehension regarding non-acceptance is the state of the righteous.