I don't know who has a better case, but you are admitting here that there is a case.
To the best of my knowledge, the Airbus case against Boeing is that Boeing's space and military contracts provide "indirect" subsidy to Boeing Commercial because revenue from those contracts can be used to shore up the commercial side when it suffers a downturn and that knowledge gained on the defense side can be used by the commercial side to make it's products better. To date, I don't believe our government has cut a check directly to Boeing, but I do know for sure that Airbus was founded and to this day survives on DIRECT cash subsidies from the member governments that make up it's family of companies.
If the fedgov does cut a check to Boeing as a way of bailing them out of this crisis (which I don't think they will do, nor do I think it is necessary), then that would be a direct subsidy on par with what Airbus has received going on thirty years now.