Hi Roquen,

Can your little boy lift his head? My son started to tummy sleep as soon as he got mobile too! i freaked out and was so worried he would suffocate, but he didnt! He is probably just comfier this way! You could try popping him on his tummy to start with and position his head iykwim!
At least he is right next to you, so you will be able to keep an eye on him!

HTH good luck xx