How do I help my brother? Martha's Vineyard, no mortgage, buy

[Samuel Carmichael]

Hi Everyone, 

A family member of ours has 2 houses on one lot in Martha's Vineyard.

She owns it 50/50 with with my uncle  "TIM"and there is no mortgage. 

TIM wants to be bought out for 300K, but my aunt wants to stay 50/50 with US NOW.

What is the simplist way to finance and buy out Tim, but keep my aunt on the mortgage?

*****My aunt doesn't necessarily need to stay on the mortgage but wants to retain ownership 50/50 "somehow until she passes. Where we then have 100% control like she wanted.

Thoughts?