Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh.

It is one thing for you to witness your father’s cremation – who is not a Muslim – and thus ordered his body to be cremated. It is, however, another matter for you to wear urn charm containing his ashes as a necklace or keeping his ashes in an Urn inside your house.

Islam teaches us to bury the body (or ashes in this case) and not to carry them around or keep them at home if you have a choice.

I am assuming you are talking about your house. If, however, the house belongs to your father then the case is different as you are not accountable for his actions.

Almighty Allah knows best.