I'm not sure that a grid penalty will achieve much in this instance. SV has one of the four best cars on the grid so where ever you make him start he's still likely to end up in the top four which is hardly much of a punishment. For me he should be disqualified from the results of the Azerbaijan GP, which is what should've happened on the day.
IIRC it's no too late for them to do that. A more likely result would be a race ban from an upcoming race should they decide that what he did warrants exclusion from a race result. I suspect what we'll see will be a 10 place grid penalty, as that's far less likely to have Ferrari dragging them through court appealing a race ban.
Having said that, it's sounding like they may be looking into whether or not they can tie this latest offence to his previous issues from Mexico last year. They'd have to twist and turn a bit to make it stick, I think, but it seems the FIA does want to make an example out of him.