Purchasing a house and giving it out on rent

1. Some one is on rent and they are still on rent and he has sold his house for 27 lacs and he has not still enough money to purchase a house in which all family members be settled. And now he is trying to purchase a house in a sense so that he can fulfil his current financial problems (for giving current rent in which they are still living), through rent income. It is permissible in Islam to purchase a house and allow it on rent , the income of this house is use for the rent of a house in which someone is rented.

2. It is permissible in Islam to invest the payment of sold house in a National savings centre in that sense to gain the fixed amount for a month (e.g. 9000) so some one can fulfil his financial problems (for giving current rent in which they are still living).