is there any way to make a diy ro di filter?

No.

Unless by DIY you mean to buy the RO membrane, housing, and all the components then plug them in. Then yes. But an RO isn't exactly something you can build from cellophane and PVC pipe from Mitre 10.

thanks u thats wat i was thinkin, but my dad was like there must be a DIY version, no i need to find 1

They are basically a fine filter that uses a semipermiable membrane which is so fine that it needs to be backwashed so getting that sorted would not be easy.

I don't know how you'd do the ro part, but the di bits easy, just add the resin to a filter