What is the Sharia ruling on returning the engagement gifts to the fiancé who broke off the engagement, and is it permissible for the brother to demand them or not?

As long as the suitor has not entered into a marriage contract with you, you have no right to what he paid from the "engagement gift" (shabka). It must be returned to him because it is part of the Mahr (dowry) or a gift given due to the impending marriage, and he can reclaim it if the marriage does not take place. The suitor leaving you is not an insult; rather, it might be good for you. Therefore, you should think well of Allah and entrust your affairs to Him, for Allah is more merciful and more knowledgeable of what is best for us. Optimism and thinking well of Allah are characteristics of a believer and provide energy to face difficulties. Fears seize a weak heart, so be keen on increasing your faith and strengthening your connection with Allah.