Should I or my brother donate the value of the mobile phone that I bought with money collected from my friends under the pretext of charitable work, and which is now in my brother's possession?

The sister who asked the question must thank Allah Almighty for guiding her to repentance and increase her good deeds. She must return the usurped money to its owners, as her disposal of it is invalid. She must return the value of the money, and it will then become her property. Then, she has the choice to demand it from her brother or to waive it for him. Her brother is not permitted to refuse to hand it over to her.