Can anyone explain if this guy I know is pretending to be a LTC?

My father was in the101st and I grew up near Fort Campbell. Rest his soul. As a Marine veteran, I have never heard of a nurse joining the reserves as a LTC. Maybe it might happen if he were a surgeon with a critical shortage focus in the OR. Not sure but. I'd say fraud. What he's done doesn't rise to the level of stolen valor. However, it does display certain character flaws and you should avoid this fake. I would not call him a friend after such a deception.

Sounds pretty odd

post his picture here so we can pick it apart

As a long time US Army Reserve member now retired, I want to remind those here that there‘ve indeed been cases of nurses joining the Reserves at later ages, due to the shortage of nurses and doctors on the Army’s medical staff. But, (and I emphase “BUT” ) -…there are two simple points I‘d like to make. Normally a Doctor or Specialist, is promoted to the rank of 03 otherwise most receive a commission to 2nd LT., but some have received -a direction above O1 on special occasions. Nurses EMT or surgical nurses could receive a higher promotion, but that would be on a case by case basis, however, I‘d generally call BULLSHIT.. on the age requirement. Age requirement is 40 at the time of commission, for retirement otherwise they won’t accept you. Age 44 and older is a No-Go, because it’s impossible to offer retirement of less than 20 at the onset of enlistment? Of course there are circumstances such as;- if that servicemember {he/she } has prior credible service then that would cumulative to the age requirements! As age 60 is the set for the “MRD {Magatory Retirement Date}” or age for all unless signed by a two star or higher.
Lastly, that individual wouldn’t be assigned to an active duty Division, but to a field unit or hospital then attached to Fort Campbell but is not assigned for pay and promotion purposes unless through a Pentagon option of a program such as holding a billet space and very well might have their Division HQs as the 101st but that’s a different animal - I doubt it, due to most reserve medical staff assigned to a Medical Reserve Unit and not an Active Duty Unit due to the supervision and money allocated for pay etc,. It all must come from from other funding as well.
But what do I know, I’m Retired! (I would still call BS)!!!

It can happen - it's highly irregular and thus chances of happening are very few. In my early career, I knew a doctor that had retired from private practice. The military did recruit him and he came on as a LTC. But his medical skills were such that he was needed. While he was assigned like other medical personnel - one of his duties was to teach other doctors the skills he had.

Most doctors are brought on as an O-3 (Captain) while RNs are normally brought on as an O-1 or O-2. My brother was offered O-4 right out of med school, but he had served 4 years as a combat medic with combat experience. There are nurses who come on as O-3 and maybe O-4 who have a lot of other things - prior service, certain specialties, etc.

So to truly answer your question, would need to know more. But on the surface of things - highly doubtful

There are circumstances, especially in the medical field, where officers are accepted with a higher rank, however I am not sure of those stipulations. Also, I am not sure if there are exceptions for age, as each branch has their own rules. I believe the maximum accepted age anywhere is 42 years old. And I also believe that he would be required to go through months of training as a cadet, candidate , etc before he could wear any officer rank. Does anyone here know if 101st even has reservists?! And even if they did, I don't imagine they would assign the noobs to a high speed unit such as that.

Based on a quick search, it appears as though it's possible. Here's 300 Guardsman who are part of the 101st airborne:
https://www.army.mil/article/177403/tennessee_and_kentucky_national_guard_soldiers_don_101st_airborne_division_patch

Additionally, many units train under the umbrella of the 101st, even though they're not technically part of it. This may be simply a bit of overstatement on the part of your friend.

As for the rank, I believe it's absolutely possible. Based on the credentials of your friend, those in the medical field are often given a rank that coincides with the rough responsibilities/benefits for which they have trained in the private sector.
https://www.medicineandthemilitary.com/officer-and-medical-training/military-officer-training
"If you enter as a licensed physician, your rank will typically begin at captain or major (Army/Air Force), or lieutenant or lieutenant commander (Navy), but it may be higher depending on where you are in your career. When you apply to join the Military, a professional review board will evaluate your work experience and prior service, if any. Once your rank is determined, it must be approved by Congress or the Secretary of Defense. This process may take several months."
If your friend is a Nurse Practitioner, or specific RN specialties with lots of experience (I would think at 45, he would!) it's quite reasonable to make the logical leap that they could come in as a LTC.

My 2-cents, anyway.

That's only a description of "possible" though. It might still be fishy. :)

Actually when I joined the Army in 2005 there was a reserve Dr. who just joined and the Army made him a full bird Col. he didn’t know anything about tactics and he was over 50, so sucks to say it’s possible

Hmmm.. i guess 101st is expanding its horizons..

He's long in the tooth if he's 45, has BS in nursing and just joined the ARMY. But the part that gives him away, is his being accepted into the 101st. Even medical personnel have to be in very good shape to be zirborne aualified.