Amen to Beracha of Reform or Conservative Rabbi

Igros Moshe (O.C. III #21) Question:Reform or Conservative rabbis who sometimes come to an Orthodox synagogue Should they get an Aliyah? Answer: It is clear and obvious that it is forbidden to give them an Aliyah since this requires saying a beracha before and after the reading. And their beracha has no significance and one should not say amen after it. That is because they are heretics. They should not be given any other honors such as hagbah and galilah or taking or returning the Torah or even closing the Ark since they are heretics. Therefore unless there is great need it is prohibited to give them these honors. If there is great need such as prevent disputes in the community or the loss of charity than it is permitted to honor them but not with an Aliyah. However to give an Aliyah to someone who isn’t observant is not prohibited since they believe in G-d and his Torah even though they violate the mitzvos because of desire not for ideology. In addition one answers amen after their beracha. Nevertheless it is not appropriate to honor them with an Aliyah since they are sinners unless there is a need such as a yahzteit and there is concern that withholding an Aliyah will cause a dispute or other problem.

Igros Moshe (O.C. II #50) Question The beracha of an Reform and Conservative (who are heretics) can it count for others and should amen be said afterwards? Answer You say you need to honor Reform and Conservative Rabbis by giving them brachos at a banquet in order to raise money for Israel. It is clear to me that their Berachos have no significance since most of them deny G-d and his Torah and obviously it doesn’t count for others. And in addition amen is not said when hearing it. .