There were 3 or 4 novus ordo priests at the "service"; at the "sermon" the "priest" said my cousin was in heaven and he had left his pain in this world.  He said he was in heaven multiple times.

The "priest" committed a grave sin.  How many other people who find life unbearable might be tempted to end the suffering so they too could "go to heaven."  Conversely, how many people there have been who would otherwise have committed ѕυιcιdє were it not for the strong teaching of the Church against it.

I don't think you should have gone ... except, ironically, because the Church merely forbids any Catholic burial, and not all types of prayer services, and it's arguable whether the Novus Ordo celebration in any way constitutes a Catholic burial.  There's no Church law forbidding holding a wake, for instance, for a ѕυιcιdє.  And one might liken the Novus Ordo festivities to an informal wake of some kind.