Welcome to YT and although I wish it was under better circumstances glad that you are here now.
I agree that it sounds like you are doing all that is necessary for Spike's care and comfort. You can't live on what if's and need to just keep moving forward. From your post I can tell that you love the little guy and that is what really matters. If and when you need to take the next step to medicating him for this issue you already have the tools in place (neurologist) to make that call. Hope you stick around to keep sharing about your little man