Kaddish for my father

My father passed away February 16 1973/(1st)Adar 14 5773.
He was from an Orthodox Jewish family who came from Prussia. He married twice and his 2nd wife, my mother was not Jewish. When he died, she had him cremated.

A Lubavitcher family helped me arrange for his ashes to be buried 7 years later. At that time I was living in Crown Heights but no one discussed with me whether kaddish should be said. The assumption on my part was a cremated Jew is buried outside the fence from other Jews. No one else discussed this with me.

This year I specifically asked whether kaddish could finally be said for my father and Rav Schusterman in Detroit discussed the particulars with me from that period and paskened kaddish may and should be said. My father was mentally addled from pain medications at age 82, worried to death about me and my younger he would leave without any means of support. He knew he was dying and was always trying to sit us down to talk about our future. After all we'd been through with him for so many years, we kept telling him not to worry, as we went on our way out to meet friends or do homework. However, cremation was never mentioned, ever. I think as well, his being cut off from his family and literally without friends, arranging a funeral and such details must have been so depressing and overwhelming for him. But I will never know, except I do know he took me to shul many times, he tried to keep shabbos and taught me to bentsch, make kiddush. He considered himself a Jew, despite his choice of bride.

I naturally turned to Chabad online to inquire whether kaddish could be arranged, but the fee is unaffordable. It's really distasteful having to shop around to have such important prayers said over a soul that was shunned by his own family for marrying my mother, then lived dependent on her (he was many years older than her) and finally suffering the indignity of being cremated, but I have no choice except to keeping looking, because he will have kaddish and the appropriate prayers said this year, G-d willing.