The death of Charles V in 1349 would have had significant consequences. In OTL, Charles’s strategy to avoid battles with the English proved pivotal in changing the tide of the war. In TTL, John II would still be defeated by an English invasion but would likely avoid being captured. In OTL, John’s capture actually worked out in favor of the French by giving them breathing room as well as making OTL’s Charles V regent. In TTL, John remaining in charge might result in Edward’s invasion army capturing Paris and Edward being crowned king of France in Reims. But even achieving these victories would not win the entire kingdom of France for Edward. England would still be suffering from a lack of both money and manpower. By most accounts, Edward was also suffering physically by the late 1350’s so I could see him signing a treaty with John with terms similar to OTL’s Treaty of Bretigny.
In TTL, Edward the Black Prince would still be given Aquitaine to rule while John II would have to contend with the mess that France would be in. I doubt John would handle ruling France as well as Charles did in OTL. France would likely remain in bad shape for the remainder of John’s rule, which could last longer (he was only 44 when he died in
1364) than it did in OTL. If he lives to around 1375, he gives the English more time to solidify their rule in Aquitaine. In TTL, it is still likely that Pedro of Castile will still lose his throne to his brother and come to the Black Prince for help. It is also possible that the Black Prince would avoid catching the illness that eventually killed him. Even if Aquitaine still revolts in TTL, it is likely John (and his heir Louis) would not be strong enough to take advantage of it.