Who do you think is telling the truth? My boyfriend or his mom?

My boyfriend's mom suddenly sent me a message saying my boyfriend borrowed money from his close younger brother and that the brother and his wife is already fighting. My boyfriends mom wanted to know what my boyfriend will do about the money.

When she sent me that message. I don't know what to feel. I told my boyfriend about it but instead of being alarmed, he said he was used as an alibi by his brother because his brother has a gambling problem and he can't tell his partner about it. He did mention this prior to this so I know this is true.

However, instead of getting mad of being falsely accused, he calmly explained it to me and then when he went back home, he told his mother that he just wants to buy something. I don't know if he is defending his younger brother or indeed he has a problem with money. In fairness to him, he rarely ask money from me if at all. I am the one who voluntarily gives whenever I invite him.

Who should I believe? Also, why is it I feel I want to pause things first until I know what to do about this? I just felt weird.

Who do you think is telling the truth? My boyfriend or his mom?
Post Opinion