Daughter doesn't want to put granddaughter in daycare

Me and my daughter are in a situation. My daughter doesn't really want my granddaughter to go to daycare or school yet. She's 5 and here you aren't required to send a child to school until 6. We both work and nobody can stay home with her. Some background information, my daughter was in an abusive relationship and got out when she was pregnant. When she had my granddaughter she went back to work and I would care for her during the day and help my daughter and my son would take over when he was back from school. Eventually I think she started going through some postpartum depression and started resenting her daughter and she just wanted to go to work, go out and come home to sleep. I tried to be sympathetic of her and I did but my granddaughter on my son more than I should have. Things got to a point where we needed someone to be with the baby full time and I had to make a very tough decision. I pulled my son out of school his junior year. It was not an easy decision. I promised I would help him get his GED. I tried to make it up to him by buying him a new PlayStation. Anything I could because he had been helping since he was 14 and now he's 16 and losing the rest of highschool. I explained that his sister experienced domestic violence and is now going through PPD and sometimes you have to sacrifice stuff for your family. My daughter started to spiral more so my son became more of a full time dad than uncle while me and my husband handled our daughter. I meant to help my son with the GED stuff but I got caught up in work and my daughter was working and then going on. We all just forgot. He's 19 now and moved out a few weeks ago. He does love his niece like a daughter but said that his sisters abuse was 6 years ago. She went through depression 4 years ago, she needs to grow up and be a mom and she's not gonna be one if he's raising her child. So he moved out and went to stay with a friend and is working towards his GED. He is right about her needing to grow up now and now that he's gone she has been forced to be a mom the last couple weeks but we can't afford to stay home and neither can she. I told her to apply for a DHS daycare subsidy but she doesn't want her daughter in daycare. She technically wants to also homeschool but she knows we don't have the resources. She should just put her daughter in school but she doesn't want her in daycare or in school until she legally has to put her school. I'm not sure what we are gonna do. Nobody can stay home with her. She told me to ask if her brother can just come to the house and babysit and I did try asking if that was possible but my son said only if we pay him and he's charging us 20 an hour to make up for all the unpaid free babysitting he's been doing since he was 14. We don't have that kind of money and I think that was more or less just his way of telling us no because he was in a way parentified. My daughter isn't giving any real options here. She needs to either put her in daycare or put her in school but she starts talking about the dangers of both. Okay than what is the option?!