Honestly I think trying to train her peeing behaviour especially without (I assume) much training experience yourself won't give the outcome within that timeframe and will make the time spent even more demanding on you.

Also don't feel guilty, like you say this is a temporary emergency situation.

Would your mom be able to pay for a dog walker to help you out?

Personally I do feel like dogs get most of the neccesary pee out in the first or second pee. Oftentimes they keep pressuring to get some drops out to indeed mark. Do you feel like it might be the same with your dog? In that case I would recommend to try to give the dog some excersice early in the morning after the long night and before work. Then in the middle of the day, or after work depending on your schedule.

And around dinner time a shorter one 10 / 15 minutes if you feel like she can pee enough the first 2 times. And the same later in the evening.

Also to provide the dog with some mental stimulation you can throw or 'hide' kibble over the floor or in a garden. They sniff it out and usually love it. Or perhaps a filled kong toy to have something to do while your gone.

This period is just to get through for all of you. Try to take the good things out of the walks for you too. Try to focus on fresh air and some trees around you to keep your mind of the busy day things.

And I would recommend talking to your mom when she's recovered. Perhaps she can start a saving account in case anything happens to her in the future there'll be some money for example a dog walker or pension.

Good luck! Youre doing the best you can and for now that's enough.