New caregiver for father with brain tumor

I have been living with and caring for my elderly father since he received a diagnosis of a VERY likely terminal brain tumor about three months ago. I cook, clean, dress him, bought him a lift chair, clean him after "bathroom accidents," coordinate his meds and nurse visits with hospice, do his shoppung, get him to and from the bathroom and everything else I'm sure you're all familiar with. My main frustration is that when family and visitors come in groups, they tend to want to do things that only two or more people can occomplish together, but are not practical or sustainable for me to occomplish when I am alone with dad (which is at least 80 percent of the time). Things like lifting him from non-lift chairs and getting him up and down the stairs and to and from the bathroom multiple times throughout the night (i am an average sized man and he is about 100 pounds heavier than me and is having increased difficulty walking). I find it difficult to sleep because I never know when he'll need help, whereas family tend to come for a short time, put on a great show and then go home to sleep. I wish I could communicate two things to visitors and family: if you want to help dad 1. Help me find practical solutions to problems that occur EVERDAY 2. If you do want to take over and run the show, then do so and let me nap-- don't give me extra tasks to perform or wake me from the first sleep I've had in three days because "we're all having cookies now!" Sigh....