What the Pope actually said (from the official translation of the Italian) was
Looking at those five loaves, Jesus thinks: this is Providence! From this small amount, God can make it suffice for everyone. Jesus trusts in the heavenly Father without reserve; he knows that for him everything is possible. Thus he tells his disciples to have the people sit down in groups of 50 — this is not merely coincidental, for it means that they are no longer a crowd but become communities nourished by God’s bread. Jesus then takes those loaves and fish, looks up to heaven, recites the blessing — the reference to the Eucharist is clear — and breaks them and gives them to the disciples who distribute them... and the loaves and fish do not run out, they do not run out! This is the miracle: rather than a multiplication it is a sharing, inspired by faith and prayer. Everyone eats and some is left over: it is the sign of Jesus, the Bread of God for humanity.
I'm not sure what's unclear about this: the five loaves and two fish were not more than five loaves and two fish, but that small amount of food was successfully shared between the people present. The fish did not suddenly multiply to become five thousand fish and each person get one; they remained two fish, and each person received a part of those.
That is, rather like the widow's jug of oil [1 Kings 17:8–16], the five loaves and two fish were never exhausted. Not only did they not run out, but as well as feeding everyone there was loads left over. This is what Pope Francis means by "they do not run out, they do not run out!"
The bible account does not say that the people brought more than that with them; only that one boy came prepared and he fed everyone. This is the miracle. Everyone shared the boy's meal, and received their fill.
This was part of Pope Francis' sermon on the Sunday after Corpus Christi. The Pope draws an analogy between the sharing of five loaves and two fish such that all in the multitude receive some of that food which Christ makes possible, and the Eucharist, where all receive the completeness of the Body of Christ in a single small particle.