It is true that the Prodigal Son only needed a sandwich and a bed?

Phil Johnson posted a quote by Vince Havner the other day. Here it is:
"If they had a social gospel in the days of the prodigal son, somebody would have given him a bed and a sandwich and he never would have gone home."
That resonated with me because I'd just an hour before finished listening to Tom Pennington's sermon at Shepherds' Conference 2018 about the Mission of the Church. He opened his sermon with refuting the social gospel AKA social justice, and went on to convincingly and convictingly exhort to his listeners about our true mission. Matthew 28's passage known as The Great Commission is our true and only mission.

Tom Pennington during his sermon, asking about the Social gospel AKA Social justice AKA Missional:
Instead of social gospel the new label became social justice. Its rebranding of liberal theology remains. The priority of social justice has become extremely popular even among those under that broad term evangelicalism
The question is this, is this redefinition of mission a biblical redefinition? Or, is social justice either the church's primary mission, or part of the church's primary mission? What does the scripture say?
Pennington went on to read the following passage, stating that nowhere in scripture is our primary mission clearer.

Now the eleven disciples went to Galilee, to the mountain to which Jesus had directed them. 17 And when they saw him they worshiped him, but some doubted. 18 And Jesus came and said to them, “All authority in heaven and on earth has been given to me. 19 Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age. (Matthew 28:16-20)

Here is GotQuestions with a definition of The Social Gospel:
The phrase "social gospel" is usually used to describe a Protestant Christian intellectual movement that came to prominence in the late 19th and early 20th centuries. Those who adhered to a social gospel sought to apply Christian ethics to social problems such as poverty, slums, poor nutrition and education, alcoholism, crime, and war. These things were emphasized while the doctrines of sin, salvation, heaven and hell, and the future kingdom of God were downplayed. Theologically, the social gospel leaders were overwhelmingly postmillennialist, asserting that Christ’s Second Coming could not happen until humankind rid itself of social evils by human effort.
Another explanation I liked as to what the Social Gospel is comes from a secular Australian website I'm unfamiliar with, called The Conversation:
The social gospel's origins are often traced to the rise of late 19th-century urban industrialization, immediately following the Civil War. Largely, but not exclusively, rooted in Protestant churches, the social gospel emphasized how Jesus' ethical teachings could remedy the problems caused by "Gilded Age" capitalism. 
Movement leaders took Jesus' message "love thy neighbor" into pulpits, published books and lectured across the country. Other leaders, mostly women, ran settlement houses designed to alleviate the sufferings of immigrants living in cities like Boston, New York and Chicago. Their mission was to draw attention to the problems of poverty and inequality – especially in America’s growing cities. 
Charles Sheldon, a minister in the city of Topeka, Kansas, explained the idea behind the social gospel in his 1897 novel "In His Steps." To be a Christian, he argued, one needed to walk in Jesus’s footsteps. 
The book's slogan, "What would Jesus do?" became a central theme of the social gospel movement which also became tied to a belief in what Ohio minister Washington Gladden called "social salvation." This concept emphasized that religion's fundamental purpose was to create systemic changes in American political structures.
So that is the social gospel. I don't know who said it first, but the phrase goes something like this: "If you have to put any adjective in front of 'gospel' it ceases to the the Gospel." The phrase refers to newly coined movements like 'prosperity gospel', 'social gospel,' 'health-wealth gospel" and the like.

With that foundation laid, the clarification I saw from Phil Johnson follows-
"I was surprised at the number of people who seemed confused by the Vance Havner quote. Here it is again, with an explanation. 

The social gospel is not Christian altruism. For a great sermon on The Prodigal Son and how caring for his immediate temporal needs would not have helped him, HB Charles explains well, here.

For a great sermon on the actual mission of the church, Tom Pennington convincingly brings it home powerfully at this year's Shepherds Conference as already mentioned, here.

As Mr Pennington said, a refutation of the social gospel/social justice/missional is not a call to ignore needs of the people around us. Christian charity meets people's needs. But as far as a heavy emphasis and/or a reorientation of our mission toward Christian acts of charity with intent to bring economic justice or material harmony to the world? No. Just no.