The Prime Minister's Relief Fund was established by Jawaharlal Nehru & a clause in it says that this fund can be used only with the consent & signature of all the committee members.
Nehru also put the President of the Congress Party as a committee member in the PM's Relief Fund.

Now think when it is a govt fund then why should president of any political party made trustee of that fund? Even today, Modi cannot spend money from the PM Relief Fund without the signature or consent of Sonia Gandhi. It is a frightening truth.

So Modi created a new fund PM Care to be free from the clutches of Sonia Gandhi.
Trustees of this fund are PM, FM, Defense Minister & Home Minister & even if the govt changes in the future, then the govt will be able to use this fund without any political interference.

No matter how anti-Modi you are personally, but you have to believe that when it comes to the interest of the country, Modi ji works above party politics. Otherwise, they could have made the BJP president its member but he did not do so.