What does this basement floor drain look like beneath the surface?
The softener drain line is supposed to be air gapped about 2" from the drain water level to prevent growth of bacteria working its way back up the line.

If you fasten your lines to a piece of double strut (or other blocking) so they terminate  above the drain with a 90° fitting, then they can drain into the opening without a bowl. You could even extend the down leg into the opening to prevent splashing, as long as the softener doesn't touch anything.

Or, look for an adapter that could be inserted into the throat of the drain to add the bowl above.

Or, you will have to dig it up and replace it with your choice.