Start with the person, not the product. If your parent still moves around in bed and shifts position on their own, a good static foam mattress is usually plenty and it's quieter, simpler, and cheaper to run. If they spend most of the day and night in bed and can't reposition themselves, an alternating-air mattress is worth the added cost and the small pump noise. That's our clear pick for higher-risk situations, and yes, the trade-off is a motor humming in the room and one more thing that needs power and occasional service.
Match the mattress to a real pressure-injury risk level. Ask the retailer which category their surface is rated for and be honest about your parent's mobility, weight, and skin condition. A wipeable, waterproof cover matters more than most people expect, especially where incontinence is a factor, so check that it's easy to clean and rated for your parent's weight. In Oakville's older two-storey homes near Kerr Village or Bronte, remember the mattress often has to get up a narrow staircase to a bedroom, so confirm delivery and setup are included rather than left at the door.
Prioritize retailers who know seniors and accessibility, not just general bedding shops. Look for staff who ask about care needs, offer a clear warranty, and can respond quickly if a pump fails. In our experience, buying local from someone who handles both delivery and service beats ordering online to save a little money, because when an air mattress stops working at 2 a.m., you want a real person to call. The trade-off is you may pay a bit more than a website, and to us that's fair insurance for something a vulnerable person sleeps on every night.