If your hair is falling out, this is quite normal in men and it all comes down to genetics.
With regard to the dandruff, you can purchase Nizorel shampoo specifically for a problem scalp from the pharmacy. There are tar shampoos also available to treat dandruff.
You can also rub baby oil to the scalp before going to bed in the evening and then wash your hair in the morning with a shampoo suitable for your hair type.
Nizeral, polytar and t gell shampoo are all great for dandruff. You could try nioxin shampoo. You get a 3 part system. Nioxin cleanser , scalp revitaliser ( conditioner) and scalp treatment. It is designed for thinning hair but would help your dandruff aswell. It will unblock blocked follicles to aid hair growth and also make the hair you have look thicker and stronger. A lot of hair loss can be genetic but there are other contributors such as stress diet health and medication
I find that some "gentler" shampoos do not clean the scalp as thoroughly as others without a little more effort. The type of shampoo you use should also depend on your hair type in terms of texture and whether it is dry, oily as well as the scalp (sensitive, dry, oily). The above suggestions can be a bit harsh, especially if your scalp is damaged or sensitive. Stress and diet as well as medications can affect hair fall, however genetics do play a strong role.
Don't go overboard with dandruff shampoos, you may not need to use it everyday. Other alternatives include a shampoo that include tea tree oil or a basic clarifying one.