Dear friend, welcome and thanks for entrusting your query here at HCM ! you son seems to have a significant heart disorder with a murmur and a possible heart failure and consequent frothing at mouth. Is it rusty red bubbly froth woth breathlessness? Does he have swelling over ankles? Does he turn bluish at tips of fingers/ tongue? This needs urgent attention and evaluation by 2D echo-doppler and may need admission. Take second opinion if one is not showing interest. The condition may be fatal. I hope you are fully satisfied with the guidance I gave. I would be glad to answer any further queries. Thank you and Good luck !