Is it appropriate for a non jw to attend a jw funeral?

Yes they can. (Romans 12:15) However the main purpose of having a memorial service is to comfort the bereaved and to give a witness concerning the condition of the dead to those who attend. (Ecclesiastes 9:5, 10; 2 Corinthians 1:3-5) Another important reason for having a funeral is to help all in attendance to reflect on the transitoriness of life. (Ecclesiastes 7:2) By attending them, Christians can give evidence of the love and respect that they had for their fellow Christian. And they may be moved to think more seriously on the meaning of life, about how they should be using their own life before God.