Start with the prescription. CPAP therapy needs one, usually after a sleep study through a London clinic or a referral from your parent's family doctor. Bring that script to a local retailer, because the machine is only half the job. The mask fit is what makes or breaks therapy, and a good shop will let your parent try several styles in person rather than shipping a box and hoping.
For an older adult, we lean toward the extra help you get from a bricks-and-mortar retailer over the cheapest online option. Yes, online can look less expensive up front, but a London store can adjust the fit, troubleshoot leaks, and swap a mask that isn't working. That hands-on service is worth more than a small saving, and the honest trade-off is you may pay a bit more than a bare-bones website.
On the machine itself, an auto-adjusting (APAP) unit suits most seniors because it responds to changing breathing through the night, so there's less fiddling with fixed settings. Ask about the humidifier, since London's cold, dry winters can dry out the nose and throat, and heated humidity helps. Check the noise level if your parent is a light sleeper, and confirm the machine tracks usage data, which their clinic will want to see. Look for a retailer with senior experience, clear warranty terms, and a quick response when something needs fixing, whether that's Old North, Masonville, or out toward Lambeth.
A word on cost. CPAP therapy in London is typically covered in part by private insurance and, for those who qualify, the Ontario Assistive Devices Program, and Veterans Affairs may help eligible veterans. Ask each retailer to walk you through what your parent's coverage will and won't include before you commit. Our advice: pick the shop that explains funding plainly and stands behind the mask fit, even if it isn't the lowest sticker.