Are you also losing hairs due to ?, because i think I am...

So i am a 23 years old man , who never drunk , smoked , not a tea drinker too and left majority of sugar/carbonated drinks long ago , I am taking care of health too but my hairs are getting thinner and falling a lot , I stopped oiling my hair 7-8 years back as I was having very oily scalp due to improper diet and it used to make situation worse for me so I have had to left oiling . Moreover due to sitting, lying , I am also not involved in exercise much . What should i do , should I start messaging my scalp again but with what kind of oil and what kind of exercises can i include to keep my hairs healthy, it's not generical because my father and grandfather have good amount of hair as per their age , not much dense like someone in their 20s but still very good