Be aware there are liabilities associated with loading for someone else and that you are required to have a special license to "remanufacture" ammunition for other people for commercial purposes (making money at it). Your safest bet from both standpoints is to invite the person over and teach them to use your equipment and let them load their own.
The other element of that goes straight to why the Hornady loads changed over time. Their old manuals had loads developed in a commercial firearm with unknown tolerances while watching for pressure signs. They were not pressure tested. Now, after using that same development process as a starting point, they pressure test their maximum loads. This is because pressure signs are really only applicable to the gun the loads are worked up in, including your friend's gun, and this has resulted in a lot of their old loads proving to be well above SAAMI standard limits.
One of the .44 Special starting loads in the old Hornady Second Edition manual was so hot that when I tried it in a Charter Bulldog it left my hand stinging. It was already at maximum for that little gun, where it had been fine in the gun they developed it in. The maximum load would have been well past sticky case extraction signs in the thin wall Charter chambers.
Regarding old load data in general: Powders, including Unique, and primers have been reformulated over time and aren't any longer an exact match to what we bought forty years ago. Case weight and capacity has changed in many cartridges, too, and pressure determining instrumentation has always been more accurate than pressure signs. So old data is obsolete data and in some instances is actually dangerous. Don't ever rely on it. Even if all those things never changed, you'd still only be certain to be able to rely on it in the exact gun it was developed in to eliminate tolerance effects on pressure. You have to think of old data as "could be possible" in some guns, but not for a moment believe that it falls within the SAAMI standard, which is designed to make ammo compatible with all guns of a given chambering.
In the Alliant manual, the maximum load of Unique under a 158 grain bullet in the .357 Magnum is 6.0 grains. Their manual loads are all maximums and they assume you will reduce the load 10% to 5.4 grains and work up your load with the gun in hand, watching for pressure signs from that number. The velocity they give is 1034 fps. That will be for a 4" barrel revolver that the test barrel mimics. In an 18" barrel that will come to about 1300 fps. If you can find a way to finance a better powder choice, that will be of benefit. The Alliant manual suggests 300-MP could get you to 2.6 times more muzzle energy.
I like the idea of the flat nose hard cast bullets. Beartooth makes a 185 grain Flat Nose Gas Checked (FN GC) bullet that is short for its weight, leaving powder space, and that will work well with one of the magnum powders. They may not have great BC's, but in a tough target like a hog you have to worry about an expanding pistol bullet opening up and stopping too soon. I've seen some photos where expanding handgun bullets have stopped in hogs before getting all way through the fat layers under the skin. If you are going to use an expanding bullet, I strongly recommend contacting the manufacturer to get their opinion on whether it is appropriate for the task at the expected velocities.