Hip Dysplaysia and Stairs

I have a ten week goldendoodle, his mom was the Golden and she weighed 50lbs, while his dad was 60lbs. In order to get to the yard, we have to go down a flight of stairs. At ten weeks, Archie weighs 14.4lbs. He has yet to do steps at all because I am really worried about his hips. Anyone have any idea how long I am supposed to be carrying him? I was thinking until he reached 12-16 weeks. Thank you!