The Qawafil Al Khair Association you are referring to seems is a local Gaza-based organization.
However the agency whose workers were killed is a U.K.- based Muslim international organization called Al Khair Foundation, founded in 2003. They have worked in disaster zones from Kashmir to Haiti.
Al-Khair Foundation is a UK-based international NGO providing humanitarian support, international development, emergency aid and disaster relief in some of the worlds most deprived areas. Established in 2003 and rapidly growing into one of the leading Muslim charities in the UK, Al-Khair Foundation also looks to tackle issues prevalent in the UK as well, such as unemployment, education, womens empowerment and domestic violence.
In case you doubt this is the agency in question, they have confirmed it:
Our thoughts are with the families, friends, and colleagues of the victims during this difficult time.
It is with great sadness and regret that we announce the demise in Gaza of eight of our teams dedicated humanitarian aid workers. They were killed in violation of the agreed ceasefire in a drone airstrike.
The exact circumstances are still being established but we refute utterly any suggestion that those who were killed were militant or in any way connected with Hamas.
It is with deep sadness and regret that we report the tragic loss of eight dedicated humanitarian aid workers in Gaza. The individuals, who were part of a relief mission, lost their lives in a drone airstrike that occurred despite an agreed ceasefire being in place.
...snip...
https://alkhair.org/humanitarian-aid-workers-killed-in-gaza-drone-strike/
When will Israel stop killing aid workers? The goal seems to be to deprive Palestinians of all necessities of life. Surely we can agree that is terribly wrong.