My kid with LDs is in college and doing well. He has dyslexia and ADHD.
I don’t know where that statistic came from, and our anecdotal responses won’t help you understand whether it is accurate or not. And even then, the only thing that can tell you whether your kid is likely to go to college is time.
Start from the fact that less than half of Americans have a college degree. So already most people don’t graduate college. Then add in LDs. That certainly makes people less likely to graduate. Add in poverty, which can overlap with LDs, and make them worse (no money for therapy and tutoring, less resourced schools) and the percentage drops again. One can see how you’d get to a low number.
If you are looking for hope, you can search here for success stories. There are many! I think my son is one of them. He struggled in school, but he has grown and matured and learned and he will graduate and get a job, I am confident.