Talk to Pediatrician on My Nephew Of Age 8 Months Is Very Weak

my nephew is of 8 months but seems like 2 months baby, he have faced the bilirubin attack while the age of 6 days, his bilirubin was increased upto 27. but through a proper treatment his disease is overcome. but from that time he is kot growing up and seems like 2 month child. we have visited many child specialized doctors but he is not growing still and weak by muscles and bones. please recommend any child specialized doctor which you considered best for him. thank you