Relationship and money

my boyfriend borrowed money from my mum for his sick mother hospital bill. it is four months now and has refused to pay back meanwhile he also borrowed money from me too since last 2 years without refunding it. he didn't tell me he borrowed money from my mum but my mum did and told me not to ask him about d money. my question is should I ask him against my mum consent because my mind is not always at rest whenever am with my mom