You need something with simple mechanics. RPGs can get quite complicated and tiresome sometimes, with multiple skills and characteristics, lots of numbers and % etc. Do not worry, though, there is quite a large number of role playing games with mechanics simple enough for anyone to grasp. As far as cRPGs go, I would suggest. Skyrim. It is an epic adventure with a great “just five more minutes” factor. Addictive, really. It also has a very simple character development system - you do stuff and the more you do it, the better you are at it. Want to hack with a sword? Hack with a sword and you’ll be a better fighter. Want to cast spells, create potions or wear particular kinds of armour? Just start doing it and your skills will improve as you go. Doing these things improve your proficiency with branches of your character - for the above it would be, in order, One Handed, one of the schools of magic, Alchemy and Light/Heavy armour. Each time you level, you receive one skill point to invest in any of these trees. Most of your choices are very clear, with obvious effects. There is room for nuance, but it only requires understanding of the game, not counting numbers. Crafting - enchanting and blacksmithing - add some of that nuance, allowing to create really specialistic builds, but frankly, you can just go with items that increase your health/stamina/mana and you will be okay. Gothic series (preferably I and II). These are very old now, but you will be surprised by how strong their fanbase still is. Gothic is famous for its well-crafted open world and atmosphere, and its mechanics are possibly the simplest there are. You have a few skills and characteristics which you improve by spending skill points and gold (you earn skill points as you gain experience and level) at teacher NPCs willing to share their knowledge with you. Witcher III. For when you want to see how this shit is really done. Witcher III has everything that makes RPG a good RPG. Wonderful story, looots of gameplay, replayability, tons of gear and large number of different character builds available. It also has a clear and relatively compact character development system. The way your character is build depends on a relatively small number of skills you select to level and use (12 skills at most out of, dunno, hundred, hundred and fifty?) and mutagens that you use to enhance them. It is really simplistic, in a good way.
With things like spells, you will need to take a look at the Spell craft Table (Chapter 4-Mulching) to get a good idea of what sort of thing each word means, and how they translate to your particular character; this gives you a rough idea of what the thing is, but you can also just read the thing without looking it up, as long as it isn’t clearly not what you wanted. This may not apply to every single class, but it should at least cover most of the classes. It should also give you insight into what the class is called, as well as a list of the abilities that it gives you. Finally, if you’re really into playing in a campaign, you’ll want to check out the Core Rules and their examples to get some things like NPC Names, Names for Monsters and NPCs, etc. If.