What is likely to be the punishment for a soldier who altered their profile?

Depends on what he added or deleted. There should be allowances for certain changes as long as they were not fictitious . Also depends on the C.C. and his outlook on the situation. most art 15 hearings are just placed in your SRB. The only way rank reduction was made known was when they saw the person removing his chevrons

Well, by the phrase "Whole military career" I am guessing he has been in for a while and is thinking of a full retirement. You have to look at that entire career up to this point and see what other things he has done against regulations, if any. Nobody is truly squeeky clean when you stay for a long time, so his history plays a big part in the punishment as well as the actual "crime" per se'. I would like to know what his motivation for this was. Is he in a unit that is active in an operational status and is this keeping him from participating fully? Is he just simply frustrated with his injury / condition, did he hurt it while in military service ore is this an old pre-service injury coming back, something that would not have kept him out in the first place? The commander would, or should have a talk with the PA or Doc who initially set the profile and determine how it has progressed up to this point, and how it is affecting his duties for starters. Next have a talk with the soldier and determine why this was done and for what reason. Once as much information is gathered, like in an investigation, then the picture becomes more clear and easier to deal with as fairly as can be. I can easily see an Article 15 in this picture, but when weighing out all the information, that could be a light punishment if tailored correctly. How does the commander view things like this, how does he view this soldier and their performance to date. All questions that must be factored in, in order to have a "punishment that fits the crime" so to speak. I see one problem and that would be what is current rank is, as if this is an NCO then it would be looked on in a different way and based on that and that alone, it could draw a much harsher punishment. So, depending on how good of a soldier he is and has been will have have some bearing on the punishment, if the commander has a fair minded approach, it could be letter of reprimand and extra duties, pay taken, and maybe a suspended reduction in rank. Of course should this get out of hand, or is pushed to a courts martial, then it could get ugly. The maximum under article 107 could be; If you are found guilty under Article 107 of the UCMJ, your sentence will not exceed:
Reduction to E-1
Forfeiture of all pay and allowances
Five years of confinement
A dishonorable discharge

So just on what I know, it could go several ways, but I am thinking at minimum an Art. 15.

Article 15 for falsifying an official document, bar to reenlistment, and a memo of reprimand..more than likely. In today's command climate, it depends on what the soldier is doing for the chain of command and NCO support channel. I've seen felonies get swept under the rug during my Army career.

Man, we had tougher sarges - they blatantly stole cases of steaks out of the back of the mess hall for the NCO club and didn’t care who saw them.

Whatever punishment he is likely to receive will most likely be between himself the 1SG & CO. This is a great site for assistance and insight on certain aspects of the military, however not necessarily one to inquire about punishment for fellow soldiers.
That being said, every company commander is different in the way in which they discipline soldiers. You will never and your entire military career find a leader that did not one point in time in their career or life make a mistake so they understand that stuff happens. All I can say is that he is a good soldier I never had issues that they should be in better shape than a soldier that has had issues before. That’s as in-depth as I would or could go.

in basic, I went 1 day over on my profile... the next day my PltnSg had a word with me noticed I still wasn't walking right and allowed the day. 3 days later I was sent back to sick call cause I couldn't walk at all. to this day, we're not sure what it was. I'm out now still unsure after the VA ran test after test. just weak joints or something

I would need to know more about what alterations he made. I would need to know more about the injury and his original limitations. And O would need to know his MOS.

If this is going to be confined to the company level, he is not going to get what he deserves, this is a serious infraction involved fraud, waste, and abuse.

The charges should be:

Article 92—Failure to obey order or regulation. The profile itself is a written order by the BN PA.
Article 115—Malingering. This covers the fact that he tried to avoid duty.

77. Article 134—(False or unauthorized pass offenses) This covers the specific alteration of the order.

I would court martial the soldier, and have him discharged. He doesn't want to, or can not, fulfill his duty. And this would send a message to the command about malingering.

He would be added to the Biden cabinet, I’m sure.

Depends on how much the chain of command and NCO support channel love or hate that soldier. I've seen soldiers get presidential treatment from command teams in spite of doing the completely wrong thing while I've seen others get confined for showing up intoxicated to first formation.

It could be anything from a counselling statement to a court martial. It depends on how severe the alteration was, and how strict the CoC is. In most of the units I was in, it would be a field grade Article 15, loss of rank, loss of pay, bar to reenlistment at a minimum. Might even initiate chapter proceedings, since he/she just proved they are of questionable integrity. In short, that ass would be toast.