Paul,
Very sorry to hear about your Mum's misfortune. My mother-in-law lives with my brother-in-law and won't be left on her own. So when he and his wife goes away she comes to us. I have absolutely no problem with that as long as she is safe and feels safe.
IMHO - get the professionals in and have a word with the local Police station and get them to send a Crime Prevention Office (or whatever they call them now) round to advise you on good security and deterrents.
You can't skimp on this kind of security purely for peace of mind.
Having been burgled once, I asked the investigating Sergeant what he would do if he found scum like that in his home..........basically he suggested giving them a hiding they would never forget and suggest they take him to court. Not so good advice
Still, like I said - get the professionals in.