looked at them

[azz]

a. He looked at them to help him.
b. He looked to them to help him.

c. He looked at them for help.
d. He looked to them for help.

Which of the above sentences are grammatically correct?

Which are natural?

Many thanks.

[Erik_Kowal]

a. He looked at them to help him.

It's unclear what this is supposed to mean. It's not a natural-sounding utterance.

b. He looked to them to help him.

= He approached them for help (or he expected them to help him -- it's not clear which is meant without some context).

c. He looked at them for help.

= He looked at them to indicate that he wanted them to help him.

d. He looked to them for help.

Same as b).