Chemist delivers but as Dint says, she doesn't always hear the doorbell, takes an age getting to the door, and more often than not misses the delivery. In that case, you might find it actually easier to collect the prescription yourself, but arrange for it to be available on your scheduled visit. You may need to get something on her GP notes like "patient cannot manage home delivery. Daughter collects, but does not live near, and therefore has to arrange collection during scheduled visits, even if this means an "early" repeat of prescription".
nora The solicitors are wrong. LPA entitles professionals to talk to you as if you were the person themselves. You may need to get your LPA solicitor to write to the conveyancing solicitor. However, this may not apply if her name isn't on the property at all - if the property is in her husbands name or her husband's and son's, then GDPR would be relevant. If this is the case, you need a good matrimonial solicitor who also has good knowledge of the law surrounding elder care.
My non-legal brain says she should refuse to pay care, get him to have a financial assessment. The home they are living in would be left out of the assessment, the other property would be included, but they wouldn't be asking her to pay for his care out of any savings she has or her share (if she has one) of the second property.
My personal view is that if he has left her off the property deeds, fairness no longer comes into it - he has broken any moral contract - and she should simply look after her own interests.