So my son is 21 months old. Hedoesn't walk yet. He cruises against furniture, will stand up in the middle of a room no problem. He can only stand without holding for about 10 minutes.he will walk with a walker.. He won't walk away he will get down on his hand and knees and crawl. He has low muscle tone.. He use to go to physical therapy once a week but the company switched and haven't gotten ahold of us for more therapies. We currently working with early intervention. Does anyone have any suggestions?? Does anyone know any excersices?? Any words of encouragement?? I'm really starting to get worried that he won't walk.