My ankles were crushed in a car accident and I still cannot squat or use stairs easily will this get better?

Depends. This all depends on the type of injury and how you healed so only your physician can tell you for sure. After a severe injury, it isn't uncommon for a joint to never get back to its pre-injury level of flexibility. Keep doing physical therapy, if it is still prescribed, and keep yourself strong and healthy and this will help.
It may not. "crushed" is a severe injury likely. The best person to ask would be your treating doc, but your injury sounds pretty severe. Sounds like you should be thankful you are even able to walk. I wish you luck in your recovery. Ask your doc if they feel physical therapy would help.
Maybe . When was your accident. Many orthopaedic injuries improve for up 2 years after the insult (provided they are treated appropriately.). To really know your chances of improvement would require x-rays to determine underlying injury and perhaps extent of arthritis as well as a thorough evaluation by an orthopaedists.