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

As an “old friend” you might just see if there is a framed commissioning or promotion certificate we all receive.—- If it’s worth the chance to embarrass him or to show your doubt.
Sometimes the better part of valor....

Almost anything is possible such as Major to Five Stars in short order—Eisenhower. The instant ranks are assigned with waivers as to eligibility for retirement and future promotion etc. Since officers are Commissioned and serve at the pleasure of the President (read Executive Branch) the needs of the service as determined by a Service Secretary determine who and when get the nod unless a specific law applies. Regulations reflect law but are not in and of themselves law (legislation). As to 101st AB, not my area.

Sadly there are a number of vets who claim things not true. A friend lost her husband, a retired United pilot, had been a Navy pilot and claimed to have flown Hueys in Vietnam and landed on ships at sea. He died of a disease listed under Agent Orange. Was helping her try to claim a VA surviving spouse allowance. I asked her to find his flight logbook. Sadly the record really damaged his reputation. He only piloted/crewed EC-121 Super Constellations Navy Surveillance aircraft, not even close to a Huey or even over Vietnam. The EC121 was equivalent to a huge TWA four engine airliner.

sounds fishy

Medical and other professions that require a higher level of education and experience may be given ranks that may coincide with their age and professional experience. You don't expect a Brain Surgeon who is 45 yrs old to be a 2nd LT? Medical personnel have a little lee way when it comes to joining at a later age. The 101 AB is a reserve unit? Sorry I don't buy that part, but it could be an active duty for training situation as a reservist filler. I've been out almost 30 years, and I have no idea how they run things anymore, because every time you look, its been changed.

Fishy?? Like a whore house in Korea? Yes yes it smells like he’s a pussy

Only active duty only are assigned to 101st Airborne.

I think you've answered your own question, Capt. I've been out a long time, but last time I checked, the 101st was an active duty unit. My son's active duty Army, (and is a LTC). We were talking about stolen valor and he told me, "It's not just vets trying to be something they weren't. You'd be surprised how much of it goes on in the active duty, reserve, and NG."

Only doctors and lawyers can join like that

Fishy like the ocean. 101st is an AD unit, no one gets LTC right off the bat (that I'm aware of). The clincher is him not being on AKO.

Yes it does. To get a direct comission as an Ltc. One would have to be an MD. Or in some field extreemly vital to national defense. A Nursing degree with no previous notary experience would likely not merit 0-5 rank upon comissioning.
Without previous military service his age would also work against him especially for an Active Duty assignment such as the 101 Airborne Division. Ask to see his ID Card and his LES leave and earning statement.
I retired as an 0-5 with 30+ years Active Duty Service. 20 years as an Officer 10.5 Enlisted.George N Roll
Master Parachutist USAFCCT/TACP/ SPECIAL OPS.

I went back on ADAF at 50. Dental Corps