Is this elder abuse?…. What can I do?

I noticed that linen was missing after it had been admired .
As the carers were so inadequate - leaving the front door open and nearly setting the house on fire- I dismissed them .

I would just say, casually, do you know where the item is, in a way that doesn't sound as if you are accusing anybody of taking it. You can usually tell from the body language and facial expression if the person you are talking to is telling the truth.
If they say "don't know" maybe ask if they can help you search your dad's house to look for it as he is upset.

When you refer to your father’s family, are they not related to you??
Just trying to figure that out.
But in reply to your dilemma, grasp the nettle and ring the relatives who visit asking innocently enough if they have seen the missing items, don’t accuse them but say that you might install a hidden camera in case someone has been coming in without your knowledge, a neighbour etc., and taking your fathers things. This should be enough to put the wind up them if they are culprits and put a stop to their shenanigans. But a hidden camera with vulnerable elderly relatives might actually be a good idea.

Boomer - I want to be casual about it and don’t want to upset anyone but they live at the other end of the country so I can’t see/gauge their body language or facial expressions. Dad is not upset, just disappointed.

I would be very concerned We only found out after my auntie died that her carer, who she thought of as a daughter had been stealing off her for years, it only came to light when my aunty at end of life went into hospital and my dad was told he couldn’t visit her as he wasn’t her next of kin. This carer had put herself down as next of kin. After my aunty died we found all her money and lots of her belongings had been stolen. We went through a solicitor but could not prosecute as we could prove nothing as my aunt had been of sound mind, and the carer said she had been given everything out of love.
Be very aware

Fallingstar

When you refer to your father’s family, are they not related to you??
Just trying to figure that out.
But in reply to your dilemma, grasp the nettle and ring the relatives who visit asking innocently enough if they have seen the missing items, don’t accuse them but say that you might install a hidden camera in case someone has been coming in without your knowledge, a neighbour etc., and taking your fathers things. This should be enough to put the wind up them if they are culprits and put a stop to their shenanigans. But a hidden camera with vulnerable elderly relatives might actually be a good idea.

I agree about the camera, I don't know if you speak to them when they plan to visit your Father but you could just say 'Oh he's ok but we have had a camera fitted for his safety, we haven't told him about it but it means we can see each room in case he falls. That should make them wary of pocketing anything, OR you might find they return the item lest you have got them on camera !!!

@Fallingstar - yes, all family and we love to see them. I”ll check in with dad first re. cameras. Just seems so unnecessary and disappointingly sad

Yes it is sad but in many cases it does become necessary. Just don’t let your dad think that you think he is incapable of looking after his own stuff. After all hidden cameras are used in countless scenarios to keep track of what is happening when there are a number of comings and goings
There is no shame in resorting to this.

If you are his carer, is there anyway you can control their visits?