Senior frenchie not well!

Has anyone got any ideas for my in laws frenchie, she is about 9 years old, had really bad upset tum all over the kitchen floor Sunday morning and was being sick, I gave them a tube of pro kolin (I keep a spare for Mia just incase) and this stopped the diarrhoea and sickness, but she smells really bad when she farts!!

I keep them telling them change her food cus it might be too rich or something, she's currently on senior royal canin so I said try some chappie and a bit of rice or pasta, they won't feed chicken as that also gives her wind.
Am I on the right track or does anyone else have any suggestions?

Sorry, just saw this now. boilded chicken breast and cold cooked rice would have been my first choice, but they could try turkey or lamb if she can't have chicken... It is difficult when they start getting older. Have they talked with their vet?

Thank Ben, apparently she's doing better now, but they still refused to change her food... They quite stubborn!

I would have taken her to live with us,as we have nursed her back to health before, but she's an old grump and doesn't like Mia so would probably add to her stress!!

Glad to hear she is on the mend. Sometimes people don't think it all through. Too bad she doesn't like Mia, but Frenchies can be grumps. Lol, I still like em though.