I'm very sorry to hear this news. How far away are you? Does he have good friends or any other family where he is? Is there any consideration of his or your moving? Does he own or rent and is his home wheelchair-accessible? Is he going to an ALS clinic? These are some of the issues to think about.
Depending on your son's income and assets, he may be eligible for Medicaid in his state, which reimburses some in-home support (Medicare does not, for everyday needs), or for "extra help" or SSI as supplemental income.
If he has enough work history, he is eligible for Medicare and SSDI if he has not applied. Depending on his employer, he may be eligible for a disability benefit as a lump sum or a monthly payment. No one will write him any checks or enroll him in anything automatically, so there is some paperwork.
In addition, he will want to complete a Will, health care power of attorney, and advance directive if hasn't yet, so that his wishes can be respected.
Other than that, many people pay privately for help for the hours and duties they need. At some point, this becomes a need for someone at home 24/7 because the person is using a machine to help breathing and requires assistance for all transfers.
It is less expensive to hire individuals such as students or semi-retired caregivers than to go through an agency or use "professionals." Generally, the more skilled levels of care are not necessary.
He will need a power wheelchair, hospital bed, BiPAP, and Hoyer-type lift for transfers, at minimum, most likely, and possibly other equipment as well. Usually a clinic writes prescriptions for these and then he works with an equipment firm to get what he needs. It's important that he interacts with the clinic regularly until he has all the equipment he needs, because there are face-to-face requirements for reimbursement.
At some point he will likely need some kind of assistive technology to operate his phone and/or computer.
As you know, the progression in ALS varies by person. It sounds like so far your son's is pretty typical. At a rough guess, just from what you have said, he might walk for another year or less, but avoiding falls is of course really important and so whenever he needs a walker or wheelchair to avoid falls, he will want to stay ahead of it. A wheelchair order process takes months, so that would be something he could ask his clinic to initiate.
If his city does not have wheelchair-accessible transit or taxi service near him, he will need to rent occasionally or buy a wheelchair van; this requires a driver. Or he might choose to move, especially if his home cannot easily be made accessible. Obviously, moves are easier to do sooner than later.
When he no longer walks, he will probably not stand for long and will need the lift and a person to operate it, to get from bed to wheelchair and wheelchair to toilet or bed, etc.
These are all just suppositions. The course of ALS is far from predictable. Having examined him and seen an EMG, his neurologist can probably be more specific if he wants him to be.
There is a lot to think about. Most importantly, if you are all honest with each other and can acknowledge your feelings and fears, understanding that not everything is shared, you will be able to help him as the parents and supports that you want to be. The paths he chooses may not be what you think should happen, but even though he will become physically dependent, the big life (and death) decisions are still his to own. He may want to know that you know that, too.
