Delayed onset muscle soreness (you can google on muscle soreness) typically peaks in about two days.
They (being research folks) used to say that soreness was lactic acid buildup, but, now, we know that most muscle soreness is caused by micro-tears in the muscle lattice / matrix.
For some muscle groups, like low back or legs, sometimes, it can take a week, or even longer, to affect full recovery.
Resistance training with weights is extremely intensive.
By reading your profile, I see you're very thin. You'll, of course, recover faster with an abundance of calories, with adequate protein, and fluids, as well as fats, and carbohydrates. If you're not eating properly, it will take longer to recover.
There is no perfect muscle soreness. If you're over-training, under-resting, or under-eating, you'll stay at your current weight; you'll not get stronger, or you'll get weaker; you'll get tired and lethargic.
Some folks, like myself, hardly ever deal with heavy soreness. After 33 years of training, I have a high rate of recovery, and, I stuff myself, too.
What works for you, may not work for your friend. It's very individual and very hard to say exactly what's right.
If you are so sore as to not be ambulatory, that's not good. Pain is usually a pretty good indicator. Otherwise, I wouldn't sweat it to much. EAT, REST / RECOVER, stimulate again. You may have really BAD recovery because of low caloric intake, I suspect. You might be over training. You can give yourself longer recovery times, if you still have soreness when you go to do that part again. I do my best, doing 1 major part per day. I often skip a day if I'm beat.