You can call nirvana and see what they have to offer? Idk as a secular person ayam don't give a shit how my body is handled after death, it's none of my business anymore, ideally I would like to have all my organs donated where feasible or maybe donate body to science (but I can't find options for this in Malaysia) and then just be cremated and thrown wherever but I guess it's up to next of kin, as a non religious person I don't care which religious rites they choose. Does your father himself care, that it has to be a non religious funeral for him?

if you want simple, just look for those coffin shop, and ask about the processes and pricing for processing your father's body when he passes away. So later on you have a rough idea what to do if he does pass away.

Because when a person is dead, there are lots of procedure need to follow one, such as getting death certificate, apply a time slot in public crematorium etc. I think such process costs about 8-10k ?

Instead of scatter the ashes into the sea, suggest just buy a place in columbarium, less than 2-3k only..

Also, make you go to at the right place, means if your dad from kwong tong, then go to kwong tong cemetery, hokkien then hokkien cemetery..