Are these sentence correct:
1) He threatened her to kill her.
2) He threatened her to give him her money.
3) He threatened her in order to give him her money.
In '1' he is going to kill her, and in '2' and '3' he threatens her in order to make her give him her money.
The structures seem the same, but they are not.
Threatening someone and threatening to do something are two different constructions, which are not used together, though their combined meaning could be achieved with a "that"-clause following the direct object:
(4) He threatened to kill her if she didn't give him her money.
(5) He threatened her that he would kill her if he didn't giver him her money.
Sentence (1) does not have the meaning of (4) or (5), so it is incorrect if you intend it to have that meaning. If you mean that he thought that threatening her would kill her and did the one thing in order to achieve the other, (1) is OK.
Sentences (2) and (3) are incorrect, at least with the meanings you have stipulated. They would be possible if we supposed that "he" and "him" are not co-referent, and that the first "her" is not co-referent with the second.