There are four routes forward with a warped neck like that. One - learn how to play slide bottleneck style. That's what I do with my 1935 Dobro...
Two, have a luthier heat the neck/fingerboard and "slip" the glue joint while pressing the neck straight. Least invasive, but very often the neck really wants to return to the way it was, and does so, particularly if the reinforcing rod has taken a set.
Three, if the amount of bow is less than 1/16" or thereabouts you can remove the frets, plane the fretboard straight, and refret. Many vintage guitars have had similar repairs, it's pretty permanent but you are left with possibly a quite thin fretboard at one end or the other, or both.
Fourth - the best solution for a long term repair - remove the fretboard, straighten the neck with heat and pressure, plane it true, remove the steel rod and replace with a modern adjustable truss rod or with one or more carbon fibre rods. Leaves you with effectively a new neck in a modern style of construction. Once you are in it this far you can easily have the neck reshaped for a modern feel as well. And stop using heavy strings on the poor thing!