TL;DR: Nobody in their right mind would accept your application, as it could ensue considerable damage to them.
I want to add the perspective of the decision maker to what’s already been said.
In all of this I assume that there is no explicit rule against recommendations by close relatives – because otherwise the situation is very clear anyway.
Also, I assume that this happens in a country where nepotism and cronyism are frowned upon and not common.
If I had to make a hiring or admission decision and the application contained a recommendation from the applicant’s mother, I would probably reject it immediately (even if I did not read a single word of the recommendation).
If it were my job to formally process applications before they get to those who actually make the decisions, I would ensure that they never even see that letter.
Also, if the recommendation was authored by somebody with a name and biography making it likely that they are related to the applicant, I would check.
The reason for this is as follows:
If somebody finds out that I made a positive decision based on an application containing a recommendation letter by an obvious relative, I can be accused of making a bad decision, ignoring a blatant conflict of interest.
It doesn’t matter whether I carefully took the conflict of interest into account; it doesn’t even matter if I actually read the recommendation – because in such a situation the burden of proof is primarily on me.
Possible repercussions include lawsuits, the end of my career, and similar.
The only way to avoid this problem is to reject your application (and the fact that you used a recommendation by a close relative will give me sufficient argument for this).
And just to be sure:
Hiding this conflict of interest is not a good idea either, because it shifts the blame for this almost entirely to you (not that you would be in a good situation if you had disclosed and were hired).