She also asks: “Is he the only spirit in the house and did he possess my son?”

He was the only free-roaming spirit and did give rise to the physical manifestations you and others witnessed. Your son’s possession was strictly the internal possession within his energy of a group of spirit meddlers attached to him and those he picked up through his vulnerability with alcohol ingestion, so there were two separate spirit phenomena involved here. Attached spirits will typically remain within their host, as a human host is highly prized and they will stake a claim and will not leave voluntarily. This is why divine help is needed to do the job.