There is no outward sin in doing that, that but it could be a sign of a deeper issue in the family relationship that needs resolution, perhaps with the help of local counsellors.
I would like to add that it is indeed recommended to perform one's prayer before breaking their fast, unless there is someone else waiting for them to break their fast, in which case it would be recommended to break fast with them, and then pray.
And Allah knows best.
Yes it is Mustahab(recommended) unless one is very weak, then it's better to do Iftar and pray afterwards
You can break your fast immediately at the time of adhan, if you are sure it is the correct time of adhan.
Thank you for your question. There is no problem with breaking your fast after the magrib prayers. In fact, in a tradition from Imam al-Sadiq (as) it is preferable to pray before breaking the fast.
May you always be successful.