I didn't know about it, quick googling shows that his dad is not a mobster. He was however arrested and charged in a high scale corruption case and fraud [1] five years back and was also charged with tax fraud in Germany before that. Since then he was released on bail and in 2014 sentenced to three years an ten months of prison [2].

Mate said in an interview that is planning to return the loan he received from his dad [3]. Also that should not impair Mate's achievements.

[1] http://www.vecernji.hr/crna-kronika/ivan-rimac-opet-na-sudu-... [2] http://www.vecernji.hr/hrvatska/afera-sibinj-svi-proglaseni-... [3] http://www.vecernji.hr/automobili/mate-rimac-posudeni-novac-...