They do, but I'm afraid it's a little strange. In Andorra (& Spain) people with a disability are graded by percentage (I know it sounds awful) and they then have a card which states their percentage of disability.
Pal-Arinsal offer a 20% discount to anyone exceeding 30%.
The realitiy is the ticket staff are unlikely to question the disability and ask for proof, they are human after all,but just to let you know their official proceedure.
Hope this makes sense,
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