Torn between Mom, Hospice and husband. What to do?

My mother was recently put on Hospice. She has a collapsed lung, and a bad heart cause by a severe dowager's hump. She has been unable to walk for a year. She lives in a nursing home. I go visit her almost daily. She pleads for me to stay when I leave. I'm pretty burned out. But I'm the only family she has left. I moved her to be near me when we moved several years ago. So she also doesn't have any friends in the area. Dementia has mellowed her but she was a horrible narscistic mother growing up. My husband has a business trip coming up and wants me to go with him, then we would continue on, on a vacation for a total of 11 days. I really don't want to go. I don't want to leave my mother alone while she goes through this. I don't want to get a phone call while I'm away and have to rush home. She does have good and bad days and my husband only sees her good days. I think she rallies around when she knows he's coming. But then again it's not like a cancer diagnosis where the end is somewhat more predictable. There have been so many times where I thought the end was near and she has recovered. I know patients can go on and off hospice. If you were me would you go on vacation? If not how can I convince my husband it's not the right time to go on vacation?