手伝う: helping with dinner and rain contributing to growth
Compare a person helping prepare dinner with warm rain contributing to crop growth. Read intentional help and a contributing condition separately, retaining the ‘also’ expressed by 雨も.
Helping the mother prepare dinner
「母の夕食作りを手伝いました。」 (I helped my mother make dinner.)
A person helps with the mother's dinner preparation. The action being assisted is making dinner; 手伝う describes contributing to that activity.
Warm rain also contributes
「温かい雨も手伝って、畑の作物がよく育ちました。」 (With help from the warm rain, the crops grew well.)
The rain is a condition contributing to the crops' growth. The も in 雨も includes rain as another contribution, so it is not being identified as the only cause.
An intentional helper and a contributing condition
The dinner scene describes help from a person; the field scene describes the contribution of warm rain. The latter does not give rain a person's intentions.
The crops grew well in this example. It does not establish a general cultivation rule that the same rain guarantees the same growth in every field.
Does 温かい雨も手伝って mean the rain deliberately chose to help someone?
Show the answer and why
No. It means the warm rain also contributed to the crops growing well. Distinguish a person's intentional help from a condition contributing to a result.