I often get calls from local arborist services offering to come and do free inspections. Perhaps you could tell her your concerns and recommend a reputable service to give her an opinion about the health of the tree. You may need to do some initial research into services, but sounds like it may be worth it if the tree is a safety concern. Or, it could just need some branch trimming. If your neighbor is on a fixed income, that may factor in to the mix.
