No solicitor would advise their client to tell the prosecution witness not to attend. That is a blatant lie by your husband. The solicitor would be committing a criminal offence; interfering with witnesses, doing acts tending to pervert the course of public justice, and would be struck off, stopped from practice, apart from any criminal prosecution.
NJ hints at selective forgetfulness. Did you make a statement for the police and prosecution? I think so. If a witness is suddenly not remembering like that, they can a) be showed the statement they made at the time, to refresh their memory or b)be treated as hostile and cross-examined. They will be shown their statement and asked about it. Is it true? When were you first aware that you couldn't remember anything? Or is it not true, in which case why did you lie when making it ? So selective amnesia about the very events which caused the case to be in court is not necessarily a pleasant route out.