Negatives in reporting

[Chicken Sandwich]

[...]
However, with some verbs, to report a negative sentence we usually make the verb in the reporting clause negative:
- 'I expect he won't come.'/ 'I don't expect he will come.' -> She didn't expect him to come. (rather than She expected he wouldn't come.)
Other verbs like this include believe, feel, intend, plan, propose, suppose, think, want.
(Advanced Grammar in Use - Martin Hewings)

Is there any particular reason why this is so?

Would you object to:

'I can't ask my parents to help me again.' -> He felt that he couldn't ask his parents to help him again.

instead of

'I can't ask my parents to help me again.' -> He didn't feel that he could ask his parents to help him again.

Why?

Thank you in advance.

[5jj]

[...]However, with some verbs, to report a negative sentence we usually make the verb in the reporting clause negative:
- 'I expect he won't come.'/ 'I don't expect he will come.' -> She didn't expect him to come. (rather than She expected he wouldn't come.)
Other verbs like this include believe, feel, intend, plan, propose, suppose, think, want.
(Advanced Grammar in Use - Martin Hewings)

Is there any particular reason why this is so?

Not that I know of. It's just one of those things.

Would you object to:

'I can't ask my parents to help me again.' -> He felt that he couldn't ask his parents to help him again.

instead of

'I can't ask my parents to help me again.' -> He didn't feel that he could ask his parents to help him again.

No

Why?

Note that Hewings used the word 'usually'. One way of saying things is more common. The other is not necessarily wrong.