It’s fine to wait to see the outcome of the ED and EA admissions…before sending RD school info. As noted, you might not have to do these…at all.
I will say…check your deadlines carefully for your admissions deadlines…and priority deadlines for financial aid.
If your student is applying for merit aid, keep in mind that those applications are often due early in the admissions round.
And lastly, it sounds like finances are a significant consideration. That being the case, why is he applying ED? If he gets accepted, he will have only that aid and your net cost. If he accepts it, he is done. The thing is…it might not be the best financial aid deal. You will never know because all other applications must be withdrawn if he accepts that ED acceptance.
And if he declines the ED acceptance because you think it is not enough…you may find that his other later schools don’t do any better.
Why not just apply RD, and have (hopefully) multiple offers to compare?
Just a thought.