Why did Folco allow him to have so much money?
The answer was that he was of age and the fortune was his.

But why had Folco let him have it before he was twenty-one, ever since he was found and brought home?
He had not had much, was the reply; at least it had not been much compared with the whole income he now enjoyed one could not bring up the heir of a great estate like a pauper, could one?
So the questioners desisted from questioning, but they said among themselves that, although Folco had been an admirable husband and stepfather while his wife had lived, he had not shown as much good sense after her death as they had been led to expect.

Meanwhile, no one had any right to interfere, and Marcello did as he pleased.
Children instinctively attach themselves to whichever of their parents gives them the most liberty.

It is sheer nonsense to deny it.

Marcello had loved his mother dearly, but she had always been the one to hinder him from doing what he wished to do, because she had been excessively anxious about his bodily health, and over-desirous of bringing him up to manhood in a state of ideal moral perfection.