Have old house, no drain in basement. Have high humidity use a dehumidifier. Is there a way to connect the drain hose from that to a what appears to be a metal of some sort sewer drain pipe? Thanks

Short answer: no.
Not without some sort of trap far enough below the humidifier to prevent sewage from backing up and to prevent sewer gasses too.
So either into a sink or into the standpipe of a washing machine.
Where DOES your waste pipe exit the house?

Cast Iron piping is difficult to work with. You can't just punch a hole in it and stick in a drain since sewer gas will come back. Using a condensate pump might work, if you elevate the dehumidifier and catch the water and pump it directly out doors through a small wall hole. The simplest thing is to dump the pan into a 5 gallon pail and water the plants.