Does Alberta Healthcare cover injuries in the USA?

American doctors and hospitals cannot take local Canadian insurance. You have to pay cash or credit card. There is no process for the providers to bill her insurance company from the U.S. and no way to collect the money from them.

Not complete coverage. The doctor would only be paid the equivalent of what a doctor in Calgary would get - and they are NOT the same amounts by any means. If possible, your mother would be better off to come home, have her abrasion looked after and then resume her holiday when it's cleared up. If she is hospitalized, then you are on the hook for thousands of dollars per day. That's why travel insurance is so important.

If she were not able to get the appropriate medical treatment in Alberta then MAYBE Alberta Health Care would cover her medical expenses for a visit to a Seattle eye doctor. She would need to have prior agreement from Alberta Health Care that they would reimburse a portion of her expenses. They would not as an example pay for any of her travel or accommodation expenses to get from Calgary to Seattle and back, nor for any companion (like you) who would travel with her. It has happened in the past where a legitimate medical need cannot be satisfied within Alberta. Good luck, you're in for a battle.

Probably not. If you had an accident in Seattle and needed treatment there they'd provide some level of reimbursement, or if it was specialized treatment not available in Canada, they'd pay, but they generally don't if you intentionally leave the province to seek treatment available locally.