damaged intestinal lining

Treatments in Chinese Medicine are not based on linear concepts of "damage" or other defined guesses of attributes.  Treatments are based on what the body is telling you and the practitioner in TCM terms.  Antibiotics are tough on the system, but what they have actually "done" to a given person varies not only in western medical terms, but definitely in Chinese Medicine terms.  As a practitioner who would be treating you, generally, you would first be looking at resolving the issues that were behind ever needing extensive antibiotic use to begin with, and then looking at helping some of the current "side-effects".  So the root first and primarily, then the secondary issues caused from duration of illness and other treatments, etc.

For general "spleen" issues in TCM terms, I would recommend reading "My Spleen is What?".  That post is introduction to the functions of the stomach/spleen system as it is defined in Chinese Medicine.  The later part of that post includes some vary basic things that may help day-to-day functioning of those systems. 

All that said, from a Chinese Medicine perspective, you have to be cautious around tonifying the stomach/spleen system if there is an ongoing, unresolved, illness as it can potentially drive the illness "deeper" into the body instead of helping the person.  A well-rounded practitioner whom you can work with over a period of months, at least, will be the best guide through that process.