I can't tell you about the new bluetooth distance, but I'm sure all of the MES remotes are similar, and mine is far better than my Mavericks ever were.
I tested it all the way to my mailbox, which is probably about 300', and it worked great----Turned it on & off, and set the time and temp from 300'. It's also the only thing I have that works from any room in my house to my smoker, including from my recliner, which has a Steel door between that & my MES.
Just don't get your Father-in-law a Gen #2. That could cause a Family feud.
Bear