Anyone find probiotics helpful? Post Whipple. 6 months

First four months post Whipple were great and husband bounced back using Zenpep and PPI. Month 5 and 6 he spiraled backwards and had most days of lethargy and stomach aches. Stomach would go off and he would feel miserable and have to lie down on sofa. Beginning 7th month he started probiotics / prebiotics and within 7 to 10 days he was off the sofa and his stomach never went “off” again. Anyone else have similar story ? He bought the brand VITAL and also uses that brand to purchase the supplement for his enzymes as the Zenpep gets pricey.
I’d read that probiotics were good for improving immediate surgical success however it’s changed his health so dramatically 6 and 7 months after surgery. I can find no research for using it at this stage.
My concern was some research mentioned that probiotics can cause return of pan.can…. But there’s so little data…
Anyone have experience in this?