Need help...?

my mom has a bf younger much than her.. one time, my mom both me a phone and her bf asked her to just give it to him (mom is not living w/us) and then he asked my mom to buy a new computer for them and they will pay half-half..but then the computer is now rested at the guy's house.. my question is..how am i gonna make my mom realize that her bf juz want her money..