My son wears a 60% grey mask which you can clearly see his eyes. Is this illegal?

It is not 100% grey which would hide his eyes.

federation rules please.

Funny you should ask, I had my first illegal eye shield today.
Federation rules require eyeshield to be clear. The casebook further states that this means 100% transmission of light. A doctor's letter does NOT superceed this rule.
A couple of states have reduced this requiremen, but only a couple.

Canadian Ruling
 

All visors must be clear unless accompanied by medical certification. (1.11.2b)

No, it's not legal.

1-5-3n
Illegal equipment. No player shall participate while wearing illegal equipment. This applies to any equipment, which in the opinion of the umpire is dangerous, confusing or inappropriate. Illegal equipment shall always include but is not limited to:
Eye shields which are not clear, not molded, or not rigid.

1.5.3 SITUATION D:
During the pregame visit in A's dressing room, the umpire notices that some squad members have eye shields which are: (a) dark, or (b) clear. The coach of A has a letter from a physician indicating that the dark shield is a necessity for the player.

RULING: In (a), the umpire indicates to the coach only eye shields which permit 100% light transmission may be worn, a physician's statement cannot supersede this rule. In (b), the eye shield is legal if, in addition to being clear, it is also molded and rigid, and attached firmly to the helmet.

BTW, 100% and he wouldn't be able to see. :cool:

Ditto on the Illegal
 

We covered this last week at our association and they are making a pretty big deal about it. Only 100% clear is permissible. We are to strictly enforce this.

Coincidentally, while we were waiting to start a Pop Warner game yesterday one of the mothers came over and asked this exact question except that her son was wearing an amber tinted shield. Same answer... illegal.

My instuctor had a case where they had told a player he had to get rid of a tinted eye shield and the player's response was that the SALESMAN had told him it was legal. I'd be wary of the rule interpretations of a guy who was trying to sell me something.

-SW---