You can ride yourself into injury that takes days, weeks or. months to recover from depending on how long you continue accumulating micro injuries.
You might review what you are doing. Are your heart and lungs stronger than your knees? In other words are you climbing hills or pushing against head winds according to what your breathing and lactic acid limits can handle but don't have a similar base fitness in your joints and ligaments to sustain repetive motion.

Icing and ibuprofen don't stop what is causing the problem, they are first aid and recovery treatment, not treatment for injury. If the problem is X hours of constant effort at Y intensity you have to STOP doing that so you can recover. ONCE you recover you carefully resume activity. It may be that what is causing the injury is 3hrs of 75% effort and that you're fine for 6hrs at 60%. It may be that an accumulation of multiple 90% efforts that last for 15minutes is simply too much. My gut sense is that you're simply grinding too hard for too long and you need to break it up with easy, easy spinning, warming up and recovery EVERY DAY. right now you risk not being able to finish if he is driving himself too hard.

Too hard doesn't have to be 150bpm for five minutes. Too hard can simply be a 75% effort for too long. It could be riding non stop for 3hrs when two two hours stretches at a slower speed carries you farther.

i had a ski injury when I was 23, a bashed patellar tendon below the kneecap. Couldn't walk for a week. 6mo later I did a long mileage tour but made SURE I rode at 60% effort or less in the first hour. A year later I joined a racing club and got racing fit but I absolutely had to warm up SLOW in the first 15, 30, 45 minutes or I was screwed for the day.

You guys have to figure out what the threshold for injury is and work under it. Like I said that threshold may not be immediately felt but you could be hitting it right out the door in the first hour of the day or half way through your day.

If you are into the first week of riding you have to figure this out, icing and ibuprofen isn't the solution, changing how you are riding is. Whether it's seat height, technique or time at a particular effort can't be diagnosed over a forum.