The SNP is in a bit of a mess, it seems.
Given MacNeil's constituency, and the impact of ferry debacles, and other issues, I think he would struggle to keep the seat in a GE. He's long been seen as Alba adjacent, so as noted, not a surprise but whoever is the Labour candidate for Na h-Eileanan an Iar will be feeling happy.
ETA - I was forgetting that the Labour candidate is Torcuil Crichton who has been doing lots on the island travel issues.