My 3yr old son has hyperextensible joints and walks on his tip toes, he tends to walk as if his legs are going togive way , hands/knees arms click?

Get him checked: Hyper extendable joints in a three-year-old in and of itself is not a problem. What concerns me, is that your child walks on his toes. It's important you get him checked to figure out what the cause of that may be. It may be as simple as stretching and some support to treat, but it's better to have him evaluated sooner than later.

See a podiatrist: Flexibility and toewalking are not unusual at his age. Most toewalkers do outgrow it. I think you might want to consult with a podiatrist or pediatric orthopedist if he often looks unstable, and what else you describe.