Thank you for your photos and question, you can use some treatment as you have very good and quality hair that can be taken care of by hair treatment prosuction or hair loss treatments.
There is no surgery or medication to make your hair generally thicker. There are hair products that add body and volume to your hair.
People with fine hair can thicken it with various products that are sold as thickeners in the pharmacy. When use, it will double the thickness of each hair so in effect you will get hair that is twice as thick. Experiment with the different products until you find one that you like