Should i postpone?

My brother was supposed to get married 4/19/20 but had to postpone due to covid. They are talking about late August but aren’t sure yet. They were talking about a longer honeymoon so what I’m asking is, should I reschedule mine and push it back so I can make sure they come? My date is 9/13/20 and I’m worried we will be so close together that they won’t come. They are having a big wedding and we are having a very very small wedding (10 guests) and they will have a harder time making their schedule work. The date is important to us but it’s a lot easier to move our event around then theirs