Hi, Unfortunate position but it happens.
A face to face meeting would be more fruitful than phone or email which are too impersonal. If he won't willingly meet, you may have to contrive a situation.
Are you aware that he might be under pressure financially other than his debt to you? Or that he has other personal difficulties? Is he gambling or drinking? If so he needs help.
He may be quite embarrassed about this, so to assist you both, tread softly, initially. You know this family member best, so you know why you gave the loan to help him and what you expected thereafter. He has let you down but why?
Going down a legal route would be costly and given the sum involved not worth it. Even if you did I think a Judge would tell you both to sit down and work it out.
Anyway, going the legal route with a family member is never a pretty sight.
You and he must talk. Good luck.