Suspension Memo without Signature

My friend receives a suspension memo from their company but the memo has no signature. But there's a note below that says "THIS IS VALID WITHOUT SIGNATURE".

Is this a valid memo? Can my friend use this memo as a proof because he is planning to file a case at Labor because of unjust reason for his suspension. Thanks.

The unsigned memo would not suffice for filing a case for illegal dismissal. There must be competent evidence to support that the dismissal of the employee violates the rights of the employees as granted by law.

Here's the memo:
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SUBJECT: Memo for Unsatisfactory Working Performance

With regards to the above subject, the company is issuing you this written memo. For several weeks, the management has been constantly identifying errors on your output papers. Despite the corrective measures/training and assistance, the company has extended you. An error continues to show up on your output papers. As per conversion with Sir *******, it has been agreed that you should take unpaid leave of absence from ******** to ********* to give time on your part to come back and focus on your assigned tasks and operate output papers free from errors and with highest working quality.

THE MANAGEMENT
(This MEMO is valid and do not require signature

Acknowledge by:

[name of my friend]

Note: Three consecutive memos shall mean termination.
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My friend already signed under the "Acknowledge by:"
Question:
1. Is this a Suspension Letter?
2. Can my still refuse to take the Leave of Absence?