My suggestion would be to wait until he finishes his residency. At that point, he will have no problem qualifying for a mortgage, employment wise, due to the fact that he had gone to school to be a doctor, and is currently in his residency. All show employment and work experience in the same line of work once he does finish his requirement for residency.
Second, by renting now you will be able to take advantage of low rental payments, depending on the area of the country you live in, and will be able to save up the 3.5% down you will need for an FHA/VA loan. Live below your means now so that when the raise does come, and he is able to practice outside of his residency, you will have the money saved up to purchase the home you really want.
Best of luck to you!