我儿子儿媳准备购买新房,由于钱款不足,就动员我把现有的房子卖掉,所得的房款给他们购新房,并说算共同出资,共同居住。考虑到就这么一个儿子,死后财产也是归他继承,于是我就答应了。老年大学的一位同学劝我慎重些,谨防今后连个窝都没了。请问,与儿子共同买房时如何保护自己的权益? My son and daughter-in-law are preparing to buy a new house. As the money is not sufficient, I mobilize the existing house to sell and the proceeds from the purchase of the new house to them. Taking into account such a son, after the death of the property is owned by him, so I agreed. One of my classmates at the seniors advised me to be more cautious and be careful not to have a nest in the future. Excuse me, how to protect their own rights and interests when buying a house with their son?