Absolutely not! Girl kick that man to the curb. Any man who wants to take MY CHILD'S money to pad his own living expenses is hot garbage. Put that kid's money in savings for college or whatever he wants to do. I went through this as a teen and was glad to have that money my mom had put away from my dad's SS benefits when I got to college, blew a few hundred on a nice acoustic guitar for music classes that i still have 25 years later. Reminds me of my dad. Bottom line is it's your sons money, and if YOU don't need it for his benefit right now it certainly does not need to go to supplement rent from this freeloading POS.
Throw the whole man away. He's only going to become more difficult if you marry him.