Living in Australia, Dad committed suicide in US

[SadInOz]

Hi all, 

First I'm very sorry for all the loss that has brought everyone here.

I grew up in the US but moved to Australia almost 3 years ago. My Dad suffered depression and committed suicide in January. My stepmother and half brother had my Dad cremated and held a memorial before I could even be contacted because I was in an area with no cell coverage that week. I was told his last wishes included that I not travel home upset, to wait to inter his ashes until I could come home. My sister has recently confided that the stepmothers family had been abusing my father and she believes they tormented him and tampered with his medications because of what she witnessed in his last few years. I am a mess and have massive anxiety but am at a loss as to what to do........