What can I do to help, if anything?

[Bejazzled]

My ds in 2nd year of uni, maths and computer science - and he is struggling. He's always coped brilliantly with the level of difficulty and amount of work until now. He gets stuck then the work builds up - he is spending hours consulting notes and tutorials etc.
I feel so sorry for him, he's frustrated and down about it.

What to do?

Encourage him to have a chat with his personal tutor, if only to let them know how he is feeling. Likely enough that they'll be able to reassure him that he's on track.

I think a lot of students struggle with the step up to second year, and the realisation that studying is actually hard work and takes a lot of time, even for very able students.

I'll do that. I think he is worried as exams are looming too.