This is an ask a lawyer question, but from my standpoint, have the husband convey his interest in the property to his wife, as her "separate and paraphernal property." The husband may still need to sign the lease pro forma if this is their homestead.
need a legal opinion & may depend on the state you are in, but my lay opinion would be that the original undivided interest would be her sole property unless she comingled it with the community estate with her husband, however the purchased interest from her sibling would, [unless stated otherwise,& purchased by her separate funds], be bought by the wife & husband together & part of their join estate.