If you eat 5-6 small meals a day how much weight can you lose in 6 months?

It depends entirely on the calorie content of the meals and your level of energy expenditure.

I you're a moderately active small person who needs 2000 calories a day to maintain body weight and you eat 6 small meals, each containing 300 calories, then you will lose weight at the rate of 1400 calories - or a bit less than half a pound of fat - a week.

Over 26 weeks this would amount to about ten pounds.

If the meals contained 200 calories you could lose up to 40 pounds of fat (if you had it to lose at the outset).

I don't know of any evidence that varying the size and frequency of meals for the same daily calorie intake makes a significant difference to rate of weight loss.