Help a family conflict

Hello all,

We have recently noticed a change with my BIL particularly with regard to behaviour and communication. Hes 27 and lives at home with his parents (always has). He is one of 3 boys (including my husband, and i would be lying if i said they all were not spoiled through childhood, by that i mean no household responsibilities, waited on, etc. 

However, recently they have been navigating a house move which brings considerable stress. My MIL has said she woud like for her and her husband to travel as they have not been away alone for over 27 years. 

My brother in law refuses. And states he will be going. My husband tries to intervene, however hes responded to with foul language and i believe by that stage people just wish to difuse a situation.

I suppose im wondering is there anything we can do to support the transition? I would like to this this wpuld lead to conversation around moving out, or for future plans (eg after parent death) as they have never been discussed. I am trying to mitigate any major family fallout

Any advice or thoughts are greatly appreciated.