There is a lot more detail to this, but I cannot really go into too many specifics, as it is this is rather lengthy!
Not the same thing I know, but my daughter who suffers from Hashimoto's Thyroid Disease and has a professional position, was diagnosed with post natal depression after the birth of her first child in her 30s. Having transferred just a few months to a new dept before maternity leave, and only able to take 3 mths leave, when she returned to work - her colleague had left and was not replaced and she was presented with double the workload. Without going into more details, after several months and authorised post natal depression leave and still no understanding and support, he son being sick and in and out of hospital, yet she did not take time off. During a further lack of support or any understanding and then an incident caused by her boss, she simply could not stand any more. Her new boss had never taken time to meet her or get to know her, yet was quick to make unfair judgement upon her and not offering any to support or advise her.
It is also worth mentioning that she has been with the organisation for around 7 years before transfer and never had any problems prior to this, also received high accolades from prior departmental heads!
Upon the meeting with her boss, designed to discuss some procedures towards a new work load she was given, before she had a chance to open her mouth, she was told that if she did not take the work on she was organisational policy, even though she never once mentioned that she would not take it! The outcome of this was just too much for her and I advised her to speak to HR - they put her in touch with the Union about it, they suggested a meeting with my daughter, her boss and a member of HR as a neutral party, as a result of this intervention she was referred to work related Stress Related Consultant in Harley Street, who advised her that she had rights due to her thyroid condition and was entitled to ask for reduced hours if she so wished.
However, the point being is, that since the last incident and seeing the Consultant her boss's attitude has changed entirely, saying that she had not realised that my daughter's baby had been ill. He has now been diagnosed as lactose intolerant and has been referred to a paedetrician for possible coliac disease - I forgot to mention during his illness he was hospitalised overnight on several occasions, my daughter stayed with him and taking work with her whilst doing so - that is how dedicated she is, and yet she was not offered any support at work. The stress is now so much less for her and she feels able to take time if her son is sick, hopefully this will not be necessary, but the shere knowledge that she can has helped tremendously. It seems that bosses will take liberties and do not always understand employees rights, employees do have rights and sometimes it takes a big jolt for them to realise this and to read up on the facts on how to deal with employee stress and illness. Obviously, we all know that some people will take advantage of this, but it is for the organisation and its management to learn to spot the difference.
All the best to your mother, judging by the facts it would seem she has 'right' on her side, but she needs a bit of 'might' - did she speak to her HR? It might be worth her either doing so or having a third party such as CAB support her in a meeting with them. Also to check out more information on
http://www.direct.gov.uk/en/Employment/ResolvingWorkplaceDisputes/index.htm
Apologies for the longwindeness of this. It just makes me so angry when hardworking well meaning people are treated unfairly, and there are so many people who unjustly try to work the system and get away with it :x I hope this example gives her some hope!