The loss of General Billotte was not a great one at this point of the game. By this time the commander of French Army Group 1 had already had his moral completely shattered and it showed. When he was moving his headquarters from Folembray to Douai after the Germans were pressing that area he was heard saying “Je suis crevé de fatigue...et contre ces panzers je ne peux rien faire,” which translated is “I’m exhausted and I can’t do anything about these tanks.” This would not be the first time he would say this and it would over the next few days become more of a mantra for him.
His last acts in command had him meeting with Weygand at Ypres on the 21st of May. Lord Gort was to be at this meeting too but was out of contact at the time due to being in the middle of relocating his headquarters. Overall there was a communication breakdown first because Lord Gort did not get to see Weygand at this meeting and on the way back to headquarter, Billotte was in this car accident and never regained conscientiousness, dying two days later of the 23rd.
Source: Dunkirk: Fight to the Last Man - Hugh Sebag-Montefiore
The pace of this war was ahead of all but a handful of French generals. Certainly Weygand, Gamelin, Georges and Billotte were totally befuddled. While some say the “Weygand Plan” was doomed by Billotte’s car accident, I doubt he could have pulled it off. The French, British and Belgians just didn’t have the ability to cobble together a mobile striking force. Millions of refugees clogging the roads didn’t help them any.
I can only think of two French combat generals who could stay with the Germans: Prioux and DeGaulle. Prioux was dealt a shabby hand when Blanchard went upstairs after the loss of Billotte, and DeGaulle was a new general still getting the feel for commanding an armored division.