What's interesting about this is that amongst other groups that magically don't have to conform to federal law, there have been court cases exempting homeowners' associations from the ADA. I'm not sure if a condo board is the same as a homeowners' association but there is some precedent supporting this type of ridamndiculous discrimination.

What this means, in practice, is that they could get away with this, even though the backyard that the mother objects to (because of snow removal) as an alternative location isn't actually accessible either.