Clenbuterol is a beta agonist. It attaches to beta receptors to perform its functions. I say all of that to tell you that beta receptors down regulate extremely fast in the body to protect you from the inevitable heart attack that comes along with overuse of longer half life sympathomimetics.
In summary, clen wouldn't be effective for long enough for you to lose that amount of weight...nor should you attempt it.
And in the words of my fiance @Mair Underwood , harm reduction information should be available to all.
Before you start anything, I’d encourage you to focus on changing up your diet, and finding some form of physical activity that caters to your physical restrictions.
Relying strictly on drugs isn’t going to do anything for you, try something like swimming.
Once you’ve made some progress then maybe look into adding something.