Minyan:Child is counted for 10th

Igros Moshe(O C II #18) Question: Can a child be counted as one of the 10 for a minyan in an emergency? Answer If it is the case that without the child there is concern that  minyan will disband than that is definitely considered an emergency even if there are other places to pray. It is possible that some will not make the effort of going elsewhere and will end up not praying with a minyan. In addition there is concern that the classes being taught will also stop even if there are classes elsewhere. In conclusion if there is concern that the failure to have a regular minyan will cause it to be abandoned then that is clearly a case of emergency and therefore one can rely on the Rema and Magen Avraham and include a child. However in general this is a dispute in the Rishonim and we are not able to resolve it and the accepted custom seems to be to not allow a child to be counted. It seems that the requirement for ten is only a rabbinic association and thus in an emergency one can be lenient. If possible the child should be at least 12 years old in addition he does not need to hold a chumash but it is best if he is holding a sefer Torah even one that is invalid. It is important that he not hold it during Shma or Amidah but it should rest on a small table  and he holds the Aitz Chaim. In addition the shliach tzibbor should not say the silent Amida but only say the Repetition out loud