Oh and it would be totally natural. no gear for him

Thats a good way to start.
Strength Training for Young Athletes
John A. Bergfeld, M.D.
Cleveland Clinic Sports Health
Head Team Physician, Cleveland Browns and Cleveland CAVS
Despite the previously held belief that strength training was unsafe and ineffective for children, health organizations such as the American College of Sports Medicine (ACSM), The American Academy of Pediatrics (AAP) and the National Strength and Conditioning Association (NSCA) now "support children's participation in appropriately designed and competently supervised strength training programs."
Experts have found that strength training programs can be safe, effective and may also help prevent certain sports-related injuries among young athletes. Recent findings suggest that strength training during childhood and adolescence may make bones stronger, a benefit which can last a lifetime. ..............
Strength Training for the Young
Strength
"In the prepubescent age, muscle weight is about 27% of the total body weight and the effect of training on muscle hypertrophy is small so that strength gains are perhaps more the result of an improvement in coordination . . . . After sexual maturation [the onset of the adolescent growth spurt], muscular development is influenced by androgenic hormones and the percentage of muscle weight then increases to over 40%." (p. 9)
Since the increase in testosterone production in adolescent children is markedly higher in boys than girls, boys will become stronger faster and to a higher degree.
Implication: If strength training is to be done with pre-pubescent children, exercises should involve submaximal resistance, such as one's own body weight, light dumbbells, or medicine balls. Sophisticated and restrictive weight exercises, particular on machines, are useless for strength-limited children. General, whole-body activities are more important and beneficial than the same exercises used for post-pubescent athletes.
http://coachsci.sdsu.edu/csa/vol32/borms.htm
Testosterone and the Life Cycle
In males, testosterone production begins very early indeed, usually at the start of the seventh week of embryonic development. Testosterone levels remain high throughout fetal life, but they fall just before birth, so they're only slightly higher in newborn boys than girls. Baby boys experience a blip in testosterone production between three and six months of age, but by a year their levels are back down. Between six and eight years of age, adrenal androgen production rises, triggering a transient growth spurt and a bit of body hair but no sexual development.
At puberty, a surge in GnRH and LH fire up testosterone production, and testosterone goes on to stimulate the growth of bones and muscles, the production of red blood cells, an enlargement of the voice box, the growth of facial and body hair, an enlargement of the genitals, and an awakening of sexual function and reproductive capacity. In most young men, testosterone production reaches its maximum at about age 17, and levels remain high for the next two to three decades. On average, healthy young men produce about six milligrams of testosterone a day.
Pri-Med Patient Education Center - Testosterone, aging, and the mind