I don't mean to sound rude at all, but if money is tight, maybe a service dog isn't the right answer for right now. That's another mouth to feed, pay medical expenses for, have money on hand for emergency medical expenses, and put simply they are a lot of work. I use a service dog and though the benefits outweigh the disadvantages most days, everyday for certain, you have essentially babysit the dog. Yeah, they're trained to handle public scenarios like champs, but the unexpected that hadn't been trained for will always creep its head when you least expect it.

On my low energy days, I don't bring my SD, I have to just... exist; I don't leave the house, because I physically cannot.

The cost of midgrade kibble, poop bags, training treats, medical expenses, yearly vaccines, grooming (depending on breed), and gear (working gear, leashes, collars, boots if you live in cold or hot climates, bowls, etc.), and toys, crates, etc. It's just a lot financially especially if your mother needs a larger dog for mobility. The bigger the breed of dog, the higher cost of vet care, more food needed, and shorter lifespans.

But if you still want to try for a service dog... I suggest adding the program you are going to get the dog from, note that you have enough to cover $2,000+ per year to live comfortably with a service dog, and adding what your mother's diagnoses are / diagnosis is.

Nice Dog