Reducing fat requires aerobic exercise, which means it takes a certain intensity and a long time (more than 30 minutes), and then your heart rate is about 150/ min, and then you start to lose weight. So there is no need to ride a bike for 4 hours every day to avoid physical strain. Unless you want to gain muscle and lose fat or your physical condition permits.
That depends on your daily diet this month. If the diet is reasonable and healthy, and the daily consumption (exercise) is greater than the intake, then the effect of losing weight can be achieved.
Finally, look at personal body data. For example, if the weight base is large, it may be reduced much, and if the weight base is small, it may be reduced less.
Generally speaking, if all the above conditions are taken into account, you can lose about 10- 15 kg a month.
I hope the landlord will adopt it and lose weight as soon as possible.