What do I do about this commission and my dead friends crazy mum?

TW- overd0se, death and suicide.

so i (M16) have a friend who passed away today. they killed themselves with a meth overdose, but before they died they commissioned me to do a painting for them. i havent finished it but I’m still going to complete it.

i found out they had died this morning to a text from their mother asking me if he had already paid for the commission, and if she could have the money back. but she hadn’t told me why she wanted it, so I said no. she then proceeded to tell me what happened to him, in graphic detail.

I started crying and walked to his house (he lives a few minutes away) and asked to see him, because I thought she was joking. she proceeded to start screaming at me and called me a few choice words and slurs that she can not say. asked me if I was dating her son and called the police on me to get the money back for the commission.

it’s only just starting to click in my mind that I’ve lost one of my best friends and I don’t know what to do. I’m gonna give the money back in the morning (it was only a tenner) but I really don’t know what to do about her. she’s called my mum 13 times and the police about me 6 times and says she will continue too.

i just don’t know what to do because she’s also telling me I’m not allowed to go to the funeral she’s planning. any advice is appreciated.