I really don't like to talk about this in public, but firstly I advise every sister to mute the words 'Khabib' and 'UFC' as some brothers who usually tweet about the deen also tweet about that and it involves the 'awrah of men.

As for those who keep praising Khabib and his father, his father was a high ranked soldier in the Soviet Army and fought in it against Muslims in Shishan. He is a murtad.
Khabib himself went to meet Putin with his father multiple times, as they were his open supporters and VIP's.

As if this wasn't enough, Khabib uses his martial art skills to train the Russian law enforcements and the army itself aswell (there is video footage of it).

Not only is his income haram due to him showing 'awrah, but his existence too due to him being a supporter of tawagheet.