Try out the custom mode . There is so much more options to make your game easier.
It's not a problem with the mode and probably not even with the difficulty setting he picked.
If he's struggling so much even in the early hours of the game, it seems clear that he simply doesn't understand some of the FUNDAMENTAL RULES of engagement of the game.
What stats to raise, what items to equip on each character, what abilities to use and against whom.
Unless he's going to give a lot more details OR post some video of him going through an encounter and showing off what he does right and wrong (and it's probably a lot of the latter) the only sensible advice I can think of is "Watch at least one or two tutorials explaining the foundational mechanics of the game" (like what a proficiency is and how to use spell slots and other abilities).
I've seen happen with other people who (turns out) weren't even leveling up their characters after the tutorial and so on.
And yeah, with a party of level 1 characters everything is a DEADLY THREAT.
What are 'normal' rpg's? If you'd ask me, I'd say that D&D is the standard from which others derived.
5th edition is also on the simpler side, as far as rulesets go.
In fact, according to many, almost to a fault.
