The first sentence is grammatically correct. The relative clause ("which helps them to be more sociable") is nonrestrictive (it can be removed from the sentence without a significant change in meaning), so it should be set off by the comma.
(Note that you could make the relative clause restrictive: "Parents should set aside some time to interact with their children that helps them to be more sociable." However, that sentence has a somewhat different meaning.)
Also, I'll point out that even though the pronoun "which" is adjacent to its antecedent (the phrase "time to interact with their children"), it is a bit far from the head of that phrase (the noun "time"); the sentence might therefore be improved with some rephrasing.
The second sentence is also OK. Some grammarians might not like the fact that the pronoun "them" is plural while the nearest plural noun before it is "parents", which is not its antecedent. However, the correct antecedent ("children") should be clear to the reader, so I think that most people would consider this fine.
However, I think that the syntax of "helping children to be more sociable" implies a meaning that you didn't intend. I might rewrite it thus: "In order to help children be more sociable, parents should set aside some time to interact with them." (I just saw FumbleFingers' response and noticed that he makes a similar point.)