I think it’s a mistake to think that donating $50,000 to a charitable organization in 5 years is more important or “better” than buying $100 of groceries for someone who needs it today.
This person isn’t trying to maximize the amount of “good” they can do, they’re trying to minimize what it will cost them because they’re greedy and unwilling to actually give something of themselves.
“Giving all you have” doesn’t have to mean taking all of your money and possessions and just giving them to someone. It can also mean earnestly engaging with the idea that we’re here to serve and elevate each other, and having faith that in doing so we will create a better world.