It's a dangerous game calling someone out as a liar when it comes to suicide. Personally, I don't want to go down that path.
What I will say is that if his intention is to explain his situation then good for him. Suicide is no laughing matter, and something that me should talk more about so it's great that he's being open about it.
But with that intention come responsibilty. He really should be talking more openly about it, and helping others understand the feelings behind it. He should be educating children, those who look up to him, about how normal it is to have these feelings and to encourage youngsters to reach out to others when they have those bad days. He should be owning his decisions in life, and accepting that the path to suicide comes more often than not from choices you make in life. He should be partnering with an association specialised in suicide prevention, as they can help him share to the point tips and experiences that will help people.
This is what a high-profile athlete who WANTS to use their experience to help others should be doing.
I'll wait to see if he does this or not and then pass more judgment on whether he's been sincere in sharing this.