Must one repeat the prayers of the days during which a traveler shortened and combined prayers, especially given that family members pointed out the error at the time?

The majority of scholars hold that whoever intends to reside in a country for four days or more is no longer considered a traveler but is treated as a resident. This is the authoritative opinion (al-mufta bihi). Based on this, your shortening (qasr) and combining (jam') of prayers were not permissible according to the preponderant opinion, as long as you intended to reside for four days or more. You must make up every four-rak'ah prayer that you shortened during this journey, because your responsibility (dhimmah) for them remains. "Allah's debt is more worthy of being fulfilled." Your responsibility will not be definitively cleared except by making up these prayers. And you must learn the rulings regarding Allah's obligatory duties from trustworthy scholars.