In this case, the transfer is void because it was donation cause mortis.

Causa mortis? What does it mean? Is it related to rigor mortis?

No. These two are entirely different phrases and the only reason they sound familiar to you is because they contain the work mortis which means “death”. The true meaning of cause mortis is “in contemplation of death”. For example, if someone, on their deathbed, gifts property to another, that gift is valid only if the donor dies from that illness. But if the donor survives, the gift is automatically revoked.

So, it’s like a conditional gift, effective only if death occurs?

Exactly. That is why the Courts treat cause mortis gifts differently from normal gifts- they’re closer to wills than to inter vivos transfers.

Interesting. So, in pleadings, if a party claims ownership from such a gift but the donor survived, then we can invoke this maxim to show that the gift never took effect.

Cause mortis is best used in succession, inheritance, property transfers, and gift disputes, especially where the intention of the donor is tied to anticipated death. You can use it in pleadings in many ways:

“The property claimed by the respondent was transferred under donation causa mortis, which lapsed as the donor survived, hence no title passed.” 

“The donee cannot claim absolute ownership as the transaction was conditional and cause mortis in nature.”