We are quite lucky at our university as we have funding to support widening participation.
For students with learning difficulties or those who are severely autistic we have a special assistant who is dedicated to just looking after that one person in terms of their mental well-being, helping them integrate and spotting when the student is having problems to take them aside/out of a particular situation. This is expensive and it needs a university to agree to fund it, but so far, we have been quite lucky in this respect, and it has made a difference.