Can you lose weight by doing 1000 squats a day?
Probably, but you will wear out your joints and possibly hurt yourself if you perform the squats with bad form.
Please conduct a balanced exercise regime that includes cardiovascular training, strength training, and flexibility training as required. If you're 50 years old and older, I also advise that you include balance training.
If you're physically frail, start with strength, flexibility, and balance training and add cardiovascular training as soon as possible.
The best way to lose weight is to eat a health diet and have a balanced and regular exercise routine. Take a look at my blog post to learn more about this.