As has been said already
Several times people have posted, "Fix the magazine", (or replace it), but I thought I should put the fine point on it more emphatically.
Of all the things that can make an automatic (self-loading) firearm fail to function with good ammunition, the magazine is, by FAR, the most likely cause. Of magazine problems, it is usually the feed lips.
I suspect your Father's magazine's feed lips. Your post seemed to suggest he has only one magazine. He REALLY should have at least two spares, and all three should work 100%. One of the main advantages of "bottom-feeders" (as autos are often called by revolver fans) is fast and reliable reloads.
Of ammunition problems, low power will cause cycling problems, short-stroking or stovepipe jams. The shape of the bullet nose is also a problem (which is often cured by changing the overall length of the bullet, switching bullets or polishing or reshaping the feed ramp.
Examine the mag's feed lips. Do they appear to have been bent? Measure the spread when the mag is empty, then again when it is full with 7 and then 8 rounds. Examine the mag lips as the action is being cycled and how the bullets hit the feed ramp and enter the chamber.
Sometimes it is possible to reshape the feed lips to factory specs and cure feeding problems (but this is a last-ditch effort, some would call it a fool's errand, or an act of desperation. It is, but since the mag is likely trash at this point, no big loss if you have already secured a replacement.)
Sometimes, the problem IS with the gun. If the way the barrel moves as the action is cycled (1911s have a toggle link, but I think EAA guns have a camming slot) is not optimal, you might get feeding problems. This will require the services of a gunsmith, probably.
You have some good points about the revolver vs auto debate.
DA revolvers are simpler to operate, but considering the internal parts, are more complex and delicate. DA revolvers are more immune to ammo variations and power levels, but more vulnerable to dirt in the works. Bury each in a kid's sandbox, then draw them, give a shake and see which one functions. The 1911 was renowned for immunity against such abuse. However, the generous clearances that allowed that reliability compromises the accuracy of the legendary 1911. Self-loaders require a narrower band of ammunition characteristics, but given good ammo are more reliable.
So, accuracy, reliability, resistance to dirt and abuse, resistance to ammo problems. You determine what you value and make your choice.
Good luck.
Lost Sheep
edit: Sometimes the problem with the mag is the recess where the magazine release engages the magazine. If it is worn (or the mag release is worn) the mag will be retained in too low a position. That can cause problems, but I don't think that is your Dad's problem. I just thought, in the interest of thoroughness, to mention it.