We don't know what to do

The family dog ​​had a seizure out of the blue on the morning of the 18th, we immediately took her to a veterinary clinic to be treated because she has been diagnosed with an enlarged heart which is a common problem in older dogs (she is about 16-15 years old, we don't know her exact age because they gave it to us, but she has her medication for the enlarged heart and she takes it) when we took her to the clinic a few hours later the doctor told us that she was getting better, but hours later he told us that she was getting worse... that she doesn't stop having seizures and that she has disseminated intravascular coagulation, that we should go see her (and that's what we did!) when we saw her she didn't react much, she is paralyzed and highly sedated, we know that she is alive because she breathes and blinks but she can't move... the doctor tells us that the seizures have nothing to do with her enlarged heart and my sister believes that she has been misdiagnosed for many years, since, when going to sleep, the dog sometimes had what we thought were nightmares because she moved strangely, barked and then peed herself. During one of these episodes, her legs stopped responding, and the doctors told my sister at the time that these were syncopes due to her enlarged heart, but now it turns out that these syncopes may have been short episodes of convulsions all this time...

The doctor took the IV to give her treatment to prevent seizures and to stop the bleeding, even with the treatment the dog continued having seizure episodes, and it seems the amchafibrim (which is used to stop bleeding) is acting very slowly so she continues bleeding a little due to the DIC, they suspect a tumor, they told us to do an MRI to see what happens but they say that even if we do it the treatment would be the same (to prevent seizures and stop bleeding) my mom and my sister say that it is not worth paying for the MRI if at the end of the day the treatment is not going to change...

Yesterday when we went to visit the dog she reacted, she was barking very loud, she moved her head and was trying to move her front legs, we fed her and she was hungry, she ate the entire plate of food, but today January 20th the doctor tells us that she is still the same as yesterday, that she has stopped convulsing and bleeding but she cannot get up, her body does not react, my sister visited her again today and she says that the dog hasn't reacted, she hasn't barked or anything, she's just breathing, probably because she's very sedated. They told us that we could keep her on treatment for as long as we wanted, but of course if this is going to make her suffer more the only way would be to put her to sleep and say goodbye to her... everything happened so suddenly, before the seizure she was walking perfectly, she was barking and everything, we don't know what to do, we still have faith and hope that she can get up, especially because yesterday it was very noticeable that she wanted to come home with us and the fact that she wants to eat means that she still has the desire (even if little) to live. This is a very hard decision and I need your help please.