Does your neighbour have someone to support her? She might be so impaired that another person has been appointed as their Power of Attorney.
It sounds like they need a regular lawn mowing / cleaning person to come into their property and maintain it. This is the responsibility of the lot owner, not the owners corporation. If she is unable to maintain the place herself, then she has to pay someone to do it for her.
Find out if someone is in charge of their finances. The person who pays the bills should arrange for a regular lawn mowing / cleaning contractor.