Need some reassurance/advice

Hi. A couple months ago my husband started seeing a naturopath and was diagnosed with methane positive SIBO. He did a breath test to find out. Since then he did a low-fodmap diet, herbal supplements and finished with Candi-bactin to kill off the bacteria (all as advised by his naturopath. Since finishing treatment he has gone on prokinetics to help his gut motility and make sure it doesn't come back. He is beginning to reimplement foods now and has become extremely discouraged as he feels like he has gone back in progress. He's started feeling bloated, having diarrhea and burping again. I've done some research and seen that this can be common when reintroducing foods but want to know if anyone else has experienced this and felt better? Or if his sibo might not be gone? He was feeling so much better but has become depressed and discouraged again since these symptoms have returned. Any advice is appreciated, thanks!