Participating in the funeral rights of Ismaili family members

I have converted to being a Muslim from an Ismaili (Ismailee) sect and Alhumdulillah, my wife and my children have also converted. I can't thank Allah Ta'ala enough for His guidance and mercy! However, unfortunately none of the other members of my family have accepted the truth. My parents, my sister, my in-laws, and my aunts and uncles are still following the Ismaili sect.

My question is about attending the funeral of these members. Especially attending the funeral of my parents. I know I can't step foot into their place of worship, so what am I to do? Should I stand outside while they do their activity, to give a shoulder to my parents and accompany them to the burial grounds and then leave? Can I take part in the naaaz-e-janaazah? This is something that is of great concern to me and I want to make sure I do the right thing.