... this according to his dad, Shaq.

The Diesel was at the Magic Wheels Toy Giveaway in L.A. doing his Santa Shaq thing (awesome, BTW) when he gave us the update on his son who underwent heart surgery on Dec. 13.

As we previously reported, UCLA doctors detected an abnormality during a routine check up and advised O'Neal that a heart procedure was crucial.

Shaq told us Shareef is continuing to focus on his recovery and hopes to be back on the floor as early as April -- which is fantastic news!

There's more ... Shaq also weighed in on Lil Wayne recently saying he thinks Kobe Bryant is better than Michael Jordan.

When we asked Shaq to pick his #1 -- he went with someone else entirely ... not Magic Johnson, not LeBron, not himself!

But, the best part of this clip is the great work Shaq continues to do in the community -- making sure every kid has a Merry Christmas!

Shaq has been doing toy drives for 26 YEARS -- and you can tell from the video ... he's just as passionate about helping out now as he was when he started.