Welcome, BookofJude.
This a case of the WTS speaking out of both sides of their mouth.
1) Non-JWs can pray and be heard if they pray for the "right" thing.
2) But non-JWs cannot pray and be heard if a more qualified person is there, such as a baptized JW, at a Bible study.
3) What if a sister has an unbelieving husband who wishes to pray for the family at mealtimes and at other times? Are his prayers acceptable, can she say "amen."
*** w90 1/15 p. 4 Whose Prayers Are Answered? ***
Pray only to Jehovah. It is useless-in fact, unscriptural-to pray to false gods,
w90 5/15 p. 12 par. 10 Fear Jehovah, the Hearer of Prayer ***
Like Cornelius, anyone today progressing toward dedication may be encouraged to pray. But an individual who is insincere about studying the Scriptures, does not know the divine requirements for prayer, and has not yet displayed an attitude pleasing to God cannot be said to fear Jehovah, have faith, or be earnestly seeking him. Such a person is not in position to offer prayers acceptable to God.
Blondie