Dear John VW : I am in Canada and aware of some of these arguments as a method by which to convince immigration authorities that said individual should remain in the country. Unfortunately, here in Canada, we also have rules governing medical inadmissibility. In other words, if someone has a medical condition which may be considered a drain on social or medical services,
the applicant may be considered inadmissible to Canada.  So, by acknowledging that the person involved has a specific medical condition, it may actually be harder to get them permanent resident status. I have no idea of the immigration legislation in the UK but you may wish to inquire of the lawyer whether similar statutory provisions exist.
Second, I have traveled to Poland three times for short visits. I am no expert on social services for persons with disabilities in that country but I did note for example that few if any public facilities there are wheelchair accessible.  According to colleagues there, services for mental health service users are custodial in nature and rudimentary at best. May I suggest that you contact Hanna Pasterny who works with persons with disabilities in Poland and advocates on their behalf?  She may be well placed to address your concerns.  Ms. Pasterny can be reached via e-mail at [log in to unmask] . Best wishes, Lilith Finkler