Bismillah ArRahman ArRaheem
Wa-Alaykum As Salaam
"Showing off" may be a misrepresentation of what your friend is doing. She is working for an NGO and their role is to help others. They need to promote that somehow and facebook is one way of doing that. It really goes back to what her intention is, and that is only something that she will know truly and is between herself and Allahﷻ.
See the following ayahs:
1. It is important to give generously without expectation or holding those you give to hostage for your generosity:
الَّذِينَ يُنفِقُونَ أَمْوَالَهُمْ فِي سَبِيلِ اللَّـهِ ثُمَّ لَا يُتْبِعُونَ مَا أَنفَقُوا مَنًّا وَلَا أَذًى ۙ لَّهُمْ أَجْرُهُمْ عِندَ رَبِّهِمْ وَلَا خَوْفٌ عَلَيْهِمْ وَلَا هُمْ يَحْزَنُونَ
Those who expend their wealth in the way of God then follow not up what they have expended with reproach and injury, their wage is with their Lord, and no fear shall be on them, neither shall they sorrow. (2:262)
2. You should give in all circumstances for the Sake of the Pleasure of Allahﷻ.... and in doing so, you can give at anytime! Imam Ali (as) did:
الَّذِينَ يُنفِقُونَ أَمْوَالَهُم بِاللَّيْلِ وَالنَّهَارِ سِرًّا وَعَلَانِيَةً فَلَهُمْ أَجْرُهُمْ عِندَ رَبِّهِمْ وَلَا خَوْفٌ عَلَيْهِمْ وَلَا هُمْ يَحْزَنُونَ
Those who expend their wealth night and day, secretly and in public, their wage awaits them with their Lord, and no fear shall be on them, neither shall they sorrow. (2:274).
3. It is OK to publish but better to conceal your charity:
إِن تُبْدُوا الصَّدَقَاتِ فَنِعِمَّا هِيَ ۖ وَإِن تُخْفُوهَا وَتُؤْتُوهَا الْفُقَرَاءَ فَهُوَ خَيْرٌ لَّكُمْ ۚ وَيُكَفِّرُ عَنكُم مِّن سَيِّئَاتِكُمْ ۗ وَاللَّـهُ بِمَا تَعْمَلُونَ خَبِيرٌ
If you publish your freewill offerings, it is excellent; but if you conceal them, and give them to the poor, that is better for you, and will acquit you of your evil deeds; God is aware of the things you do. (2:271)
In conclusion, we do not really know what the intention of your friend is, but we must assume it is for the sake of Allahﷻ and to publish your charity to encourage others to do so is in itself something that is sometimes required. People seeing the good work being done (assuming that is the case) will see that their donation is going to the right places and where they intended it to go and so are encouraged to give.