I've gone to numerous family furnerals as well as those for coworkers and non-JW family of JWs. This was as an elder and as a rank & file. Never had anyone question it. Same for weddings.
The last furneral I went to (non-JW family), my dad & brother (both serving elders) were upfront with the rest of the family (mostly JW). Only one JW family member that should have been there wasn't and the rest of the JW family thought he was way out of line.
Of course, many of them didn't bow their heads during prayer or say amen. I don't have a problem with them not saying amen and such. After all, I don't say amen to the prayers at the KH because I don't agree with them.
It really depends on the local situation but I would say that most JWs I know don't have a problem with attending furnerals.