Meaning of "He's soft, ain't he? Them giants mostly is" in "Five Children and It"

Question

From Five Children and It by E. Nesbit:

'What'll you take for him?' she said excitedly. 'Anything in reason. We'd have a special van built—leastways, I know where there's a second-hand one would do up handsome - what a baby elephant had, as died. What'll you take? He's soft, ain't he? Them giants mostly is—but I never see—no, never! What'll you take? Down on the nail. We'll treat him like a king, and give him first-rate grub and a doss fit for a bloomin' dook. He must be dotty or he wouldn't need you kids to cart him about. What'll you take for him?'

'They won't take anything,' said Robert sternly. 'I'm no more soft than you are—not so much, I shouldn't wonder. I'll come and be a show for today if you'll give me'—he hesitated at the enormous price he was about to ask 'if you'll give me fifteen shillings.'

What did the writer mean by soft? I've either two meanings, the first one is: foolish or stupid as in: soft in the head (which is informal) and the second one is smooth, which I don't think so, yet the woman said once in the same chapter a word close to "sexual attractive" that's why I've put it the second meaning into consideration.

Answer 1

Since in addition the character says

He must be dotty or he wouldn't need you kids to cart him about.

I expect that soft here refers to "soft in the head". As you already know this is not a compliment, which is why Robert speaks sternly when he denies both his softness and the children's authority to accept money on his behalf. The woman appears to be encouraging the children to sell him outright, like a possession; he offers a single appearance for what he considers a lot of money.