...is that they aren't adults. They are, to an even greater extent, unpredictable.
So long as everything goes perfectly, your son is likely to have no trouble at all. As things sometimes do, however, should anything NOT go perfectly, any deeper than 40'-50' is a lot of water to get up through. And what might be an easy fix for you, might not occur to a 13 year old.
Youngsters can be drilled in the pool, and can exhibit reasonably good skills and comfort. Then a rubber mouthpiece rotates slightly around their rental reg, so it sits slightly at an angle in their mouth, they inhale and get a wet inhale, hits them at the back of their throat, and they bail. It happens fast. I've been there when it happens. You don't want something like that to occur at 60' or deeper.
Your 13 year old is "about" to be certified. So he doesn't have loads of experience. Since you asked, my advice is to focus this trip on diving with your son in < 40' of water. There is much to see and do shallow, and it will be quality family discovery time. If you need a deeper dive, let your son find something else captivating to do on the boat while you dive deeper. If this is your first family scuba trip, take it slow and avoid any traumatic memories. The depths will still be there when your son is a bit older and more experienced.
There are reasons for the limitations. There are very few reasons to ignore them.
Wishing you and your son a wonderful trip.