Do you think it's a good idea to let my property going to foreclosure

Foreclosures cost people in many ways. You many not be able to get a mortgage for 7+ years. You can force the sale on the property or hire counsel to advise him to leave, and either pay his fair share or sign off his interest. Be sure to tell him that his credit will be equally hurt as yours in the event of a foreclosure. You can demand an accounting so you get back the money you put in first before splitting the sale proceeds (if any). Even if he leaves, if there is a mortgage, he is still on the hook for it until it is paid off. He can force you to refinance him out of the mortgage to buy out his interest. You may well need legal assistance on this.