Any fool with an acetylene torch could put the pieces back together, however; one might question quality of the results.

A proper way to repair this would take place at a shop. The first concern is fit. Does the steering stem fit tightly into the fork crown? If not tight, too bad and the resulting repair quality will be substandard. It might work and it might not.

Straight? The stem will have to be installed and square to the fork set. If not square, you will be starting out with a bent fork. To achieve straight, the repair person had better have a way to secure the pieces before attempting to braze or silver solder the joint. Silver solder would be best since it requires less heat to employ.

Once the steering stem is installed, what about the bearing race? Machining brass is hardly a good way to go when mounting a bearing race. So, once again, some more expert help will be required, assuming, of course that one wants to do the job correctly.

So, easy fix? Yup, for the person who knows what they are doing and has the skill/experience to know how to do it.

Fix it yourself and worry about the results forever, or until the repair fails and, perhaps, fails catastrophically.

Just an old fella's opinion. If it were up to me, I would seek out and replace the fork set.