people questioning my ability to care for sick grandson

I have been staying at a Ronald McDonald House with my grandson while he receives care for cancer and a brain injury that put him in a wheelchair and affected his ability to feed himself. His parents are at home with other children/work. I have been involved in his daily care, including months spent living in hospital with him. The administrators called my daughter and questioned my ability to care for him, apparently because I made a couple of suggestions regarding need for handicapped ramp at sidewalk and using meat thermometer to be certain ground beef is heated to kill e coli. His wheelchair tipped when I tried to back him off the sidewalk curb but he was not hurt in any way.
I returned home but I'm shattered, especially as gossip about this has now spread throughout our small community. I love this child more than I can express in words and we have a bond that is really special, as his therapists have observed. I'm so hurt and angry that I can't stop crying. The house manager has apologized and asked me to return but I feel unwelcome and I think his parents now question my ability. I'm not sure what I'm asking here. Just needing to vent.