Has your friend's wife ever read the care plans for these clients? (I.e before other shifts). Was restraint used & Are they trained in appropriate de-escation and restraint? Are they a 'key worker' for the client involved? Do they need to write in the 'daily logs' during /after a shift? Was an 'incident report' completed at the time of the incident? Was a body map completed at the time and for the following days. Was the 'lashing out' reported to anyone at the time? Was bruising noticed by staff on subsequent days or just by the family members. ( Questions mostly rhetorical)
Usually, when working with this client group, you would have a load of training at the start of employment which gets re-done annually. (Generic stuff that affects all clients), then, when you work with each new individual you read & sign the care plans for that specific client. Daily logs are completed by staff telling the story how the service users day has gone. Any incidents like the above would trigger an 'incident report' and possibly body map. Service users usually have a 'key worker' assisignd who updates care plans, records daily logs. Obviously the key worker might not always be able to work with the client but the aim is to provide continuity, and someone who knows the client who can pick up on things before it escalates.
Of course different facilities/agencies do things marginally differently but the above is the sort of things social services / cqc expects to see from an organisation.
Social services will more than likely investigate, possibly under 'safe' get/ section 42 (of the care act ) enquiry. But they investigate the placement, not so much the staff member.
They will be looking at whether a) procedures were in place, and b) were they followed.
From your friends perspective, they need to consider whether they followed the procedures of their organisation appropriatly. This is more of a work issue then a legal issue for her. Mostly because the family would need to "sue" the placement and not the carer/ support worker.
If your friend had read the care plan recently, but not that day. Was familiar with the service user. I wouldn't have a huge problem in reading a statement amended (signed and dated as amended of course) stating " i have read service user x's care plan when i worked with the client previously on x date & am familiar with their support needs, i spoke to key worker x or manager y who advised they're were no significant changes in needs". My recommendation would be (for staff ) to review the care plan and logs regularly. But it wouldn't worry me unduely.
However I'd be going on at the manager, not the carer. The outcome would likely be carer x has received updated training.
If your friend had never read the care plan I'd be having a field day! But again.... At the manager! However your friend needs to protect themselves and read the care plan! There might have been something in it relevant. Maybe it was emergency respite, client was unsettled and there was different guidence to normal.
Sorry I've waffled. Anyway - unlikely to be a legal issue for your friend. More likely a work issue if she hadn't followed policy. If policy wasn't in place the managers are probably sweating because safeguarding or cqc are nvestigating. Family need to sue the placement, not your friend, if they have a problem.
But more likely they just want a statement to go in the file/ give to adult services and know that adult services will want evedence that those working with the client knew their needs.
-Adults social worker.