Gum abscess but no pain - dentist says needs extraction or root canal?

My elderly mother, who is in poor health with extreme leaky gut and mast cell issues, has a painless abscess on her gum at a rear molar. The dentist didn't do an x-ray and told us that the tooth was dead. Options are extraction or root canal. Extraction may require a spacer or something else later as she is missing the tooth next to it also. He also stated that extraction would require antibiotics. I don't know how someone with severe leaky gut and dysbiosis could take antibiotics. Doxycycline is the reason for her swift decline, leaky gut and mast cell issues.

I am not thrilled with what I've read about root canals.

Can you just have a gum abscess that heals on it's on? But I guess he did other tests that tell him the tooth is bad?

She has seemed to feel poorly lately and her mast cell reactions are increasing.

Thanks for any thoughts.

I think a bridge is possible but it would likely still require antibiotics for the tooth extraction.

It is hard to get her to any appointment at this point.