Free Travel Companion Pass - criteria ?

My mother who is widowed, is retired and has a travel pass. I went onto the Welfare.ie website to see what criteria are necessary in order for her to obtain a "companion pass".

For people up to 69 years of age, your GP needs to complete a medical report and the applicant also has to give permission for release of medical information which may be needed to support your claim.

However there is a different application form for people aged 70 and over, wherein you only have to declare that you are unfit to travel alone as a result of your medical condition and you have to state what that medical condition is.

Does anyone know what counts as a suitable medical condition . Does arthritis count ?