Pretty unlikely to happen, unless France started the question sending back Mariana Victoria (and I do not believe who Bourbon would be so stupid to doing that with Louis as King of Spain). Louise Elisabeth had brought a very fat dowry and was still only 14 years old at her husband’s death.
Parma and Tuscany were Charles’ inheritance from his mother’s family so Louis would be obliged to support his brother there, specially as Charles is engaged to Philippe Elisabeth d’Orléans, younger sister of his own wife.
I think France still sends back MV.
-OTL, the move was a major slap in the face. Spain did not increase in stature during Louis' short reign, so France would still have the audacity to continue as OTL.
-the house of Orleans (from whence LE hails) is out of power
-France's foremost attention in the affair centers around marrying XV and start him pumping out an heir.
At best, Charles remains engaged to Philippe Elisabeth. They probably send her back, though. A diplomatic insult of this magnitude cannot go unanswered. If LE is still acting as a nutjob, they may take the occasion to have the marriage annulled, or send her off to a convent.
Backing Charles for Parma is a fairly easy thing. Despite international assurances, it is not a done deal though. Farnese was worried that the other powers would not honor the agreement, and had to do further wheeling and dealing to make sure it actually came to pass.