I have 4-blade ceiling fan. I realized that the motor speed is too high for a "low speed" function. It is too windy where my old father could not take it. To me, the fan's performance is good; but to the old man, it is too windy.

Can the ceiling fan still work nicely if I remove two of the fan blade to get a low air delivery? My planning is to remove 2 blades, and I think the balancing should be OK.
If the removal of fan blade is not recommended, is that any method to reduce the motor speed?

Please advise. Thank you.

Removing two blades, the fan will actually go faster.

Frequently asked ceiling fan questions - Ceiling Fans N More

What make/model is the fan? You can install a speed control, or you can install a capacitor. If you only wanted to slow the low speed you could wire a capacitor onto the pullchain. Once I know what fan you have I can give you more info.

Or, just run the fan in reverse.

You can buy a multi-speed switch for the fan at most any home center. There are 3 speeds and also a slide switch available. Do not use this if you have a remote. Does your fan have pull chnains. I would not recommend removing any blades.